Taking a bath is lawful and some scholars regarded it as obligatory on the person who embraces Islam for the first time or for the one who was an apostate. When performing Ghusl, the new Muslim or the returned Muslim pours water on the entire body with the intention of adopting Islam and repenting from the previous disbelief.
It is not necessary to offer two Rak`ahs after Ghusl, however, it is religiously recommended for any Muslim to offer two Rak`ahs after observing a ritual purification according to Hadiths of the Prophet (peace be upon him) on the issue and they are called SunnatulWudu' (the act of Sunnah of Wudu').
As for the Ayah you mentioned in which Allah (Exalted be He) says, Verily, those who believe, then disbelieve, then believe (again), and (again) disbelieve, and go on increasing in disbelief it does not
mean that whoever has increased in disbelief or repeated his disbelief, Allah (Exalted be He) does not accept His repentance, but it means, according to scholars, the persistence in disbelief until death as indicated in another Ayah from SurahAlBaqarah in which Allah (glory be to Him) says,
Verily, those who disbelieve, and die while they are disbelievers, it is they on whom is the Curse of Allâh and of the angels and of mankind, combined. They will abide therein (under the curse in Hell), their punishment will neither be lightened, nor will they be reprieved.
And He says in SurahAl`Imran, Verily, those who disbelieved, and died while they were disbelievers, the (whole) earth full of gold will not be accepted from anyone of them even if they offered it as a ransom. For them is a painful torment and they will have no helpers.
He (Exalted be He) also says in SurahAlBaqarah, And they will never cease fighting you until they turn you back from your religion (Islâmic Monotheism) if they can. And whosoever of you turns back from his religion and dies as a disbeliever, then his deeds will be lost in this life and in the Hereafter, and they will be the dwellers of the Fire. They will abide therein forever.
Allah (Glorified be He) elaborates in these three Ayahs that the matter of torment, curse, the nonacceptance of good deeds and nullifying rewards only occur in the case of dying while adopting disbelief. Therefore, scholars agreed that a disbeliever, whatever kinds of disbelief he has or how often he repeated apostasy, is accepted if he sincerely repents to Allah (Exalted be He) by giving up disbelief, resolving not to return to it again and regretting the past disbelief and wrongdoings. However, they disagreed with regard to the ruling on the person who apostasizes more than once in his life; will he be accepted and saved from killing or not? They do not disagree about the acceptance of sincere repentance as illustrated previously.
I hope that what I mentioned is sufficient in the issue. Anyhow, you should hasten to observe sincere repentance, show submission to Allah (Exalted be He) and supplicate to Him to accept from you and help you adhere to the truth and protect you from the insinuations and whispers of Satan, who is indeed the bitter enemy that aims at destroying you and other people. Allah (Glorified be He) says,
Surely, Shaitân (Satan) is an enemy to you, so take (treat) him as an enemy. He only invites his Hizb (followers) that they may become the dwellers of the blazing Fire.
The thing that helps in humiliating Satan is to observe sincere repentance; so hasten in doing so and have glad tidings with good consequence and salvation from Hell and the acceptance of your penitence if you are truthful. I exhort you to say Dhikr (remembrance of Allah by saying, "Subhan Allah, [Glorified be Allah], A lHmad Li Allah [i.e. Praise be to Allah]) and asking Allah to forgive you and supplicate to Him to confer peace and
mercy on His Messenger (peace be upon him). Among the best supplications of Dhikr is the 'word of Tawhid', namely La Ilaha Illa Allah Wahdahu LaSharika Lah Lahu AlMulk Wa Lahu A lHamd Wahuwa `Ala Kull Shaie'n Qadir (i.e. no one is worthy of worship except Allah, He has no partner, to Him belongs dominion, and to Him belongs [all] praise, and He is over all things competent) as well as other supplications such as Subhan Allah, AlHamdu LiAllah, La Ilah Illah Allah (no one is worthy of worship except Allah), Allahu Akbar (Allah is the Greatest), La Hawla Wala Quwata Illa Billah (there is no might nor strength save in Allah) and Subhana Allahi Wa Bihamdih Subhana Allahi Al`Azim (Glory is to Allah and praise is due to Him, the EverGreatest). You should ask your Lord to forgive your evil deeds saying, "I ask Allah and no one deserves to be worshiped but Him, the Living and SelfSubstantiating to forgive me and accept my repentance. (O Allah) there is no god but You. Glory is to You. Verily I was one of the transgressors. O Allah! I have done great injustice to myself and none but You forgives sins, so forgive me, and confer Mercy upon me as You are the OftForgiving, the Merciful."
I recommend you to recite the Glorious Qur'an a lot and to ponder on its Ayahs, for it contains all goodness and warns against every evil. Also, I advise you to read as much as you can from famous books of Hadith, such as Riyadh AlSalihin and Bulugh AlMaram, which contain great benefits for you and help you do good deeds, if Allah wills. Observing supererogatory Sawm (fasting) during Mondays and Thursdays and three days of every month is an act of worship and obedience to Allah (Exalted be He) and it entails a great reward and is a way to attain forgiveness of sins. However, if your mother does not agree to this, you should not displease her, for the mother has a great right and being dutiful to her is among the most important duties. She is doing so because she fears that you may become lazy out of Sawm so that you may be unable to seek your provision and your household duties. You know that seeking