These topics are always funny to me, because I wanted a ball python since I was in 6th grade. But when I asked my parents a few times for a snake and they gave me a flat out "no", I just was like "ok" and gave up. LOL
That's what I did, except I graduated college and lived in my own apartment.
Meaning... if your parents adamantly don't want a snake, even after you've showed them facts and research and caresheets you've done, there's nothing to do about that since you live in their home. It's their money too.