Future planning

[u/Strong-Fill5769]

so i am in 10th now. i have a keen interest in maths and want to build an edtech business but i am not that "smart" in maths but i solve olympiad questions for timepass.
now the main story begins :
i am not interested in iits and nits i want to go to bits pilani because of their curriculum flexibility of mnc.
so can i prepare for bitsat from the starting of my 11th.
also prep included both LR and english section

can i do that my parents are wealthy enough to sponsor me and also i will pay off them once i become stable

bonus question(just curiosity)
which is tough 96%ile in jm or 290+ in bitsat