Ive alot of things in my life that i regret... but the worst one was commiting an act of zina... this happened when I was in my early teens, and now i am turning 17 and i now am very religious praying 5 times a day, reading quran etc. I repent every single day about it and i wish it never happened. I just dont know if Allah (swt) will forgive such an evil deed. If I beg for forgiveness from the bottom of my heart will allah (swt) forgive me? And i heard from someone that all things that a child does up until puberty are forgiven.. is this true?

I just need some reassurance, and anything will help. Thank you