The beginning half does remind of Harry Potter but that is were the similarities end for me…though the “chosen one” trope seems over done to me so as long as you add your own unique twist your are good! I also hope you have some struggle between the character and the Mom because even if there was a supposed “good reason” for abandonment I think there would still be resentment and lack of trust.
“How is the Mom going to prove they are actually the MC’s mom? Why does it specifically have to be the Mom to train the MC?” are questions I think the MC should ask themselves.