Asalamu alaikum wa rahmatullahi wa barakatu,
Like many others here, I was born into a muslim family in a western country, however, in my teenage years I rebelled against islam and started taking into account different ideologies about life and what happens after we die such as studying buddhism and etc. I stopped praying and fasting and remembering Allah سُبْحَانَهُ وَ تَعَالَى and started to commit every major sin you can think of, I basically became a kafir (Istaghfarullah). As an 18 year old adult now, I am back into islam and my deen and taqwa has been the strongest in my life and it is growing stronger everyday. I have been praying all my voluntary prayers associated with the obligatory prayers and have been avoiding sin as best as I can, alhamdulillah. My question is, will all the sins I have committed in that period of from the age of 11-18 be wiped off as a clean slate? I am worried about this and I feel as if I should be praying Salat al-tawba on every sin I have committed in my life starting from puberty, which are too much to count, and remember.
Jazakallah khair!