General questions for someone who is thinking about trying?

I'm almost 16 and live in a not so accessible area of the world. I didn't know there was a cup until last summer; to be fair, I had to do weeks of Google searching to figure out what pantyliners were, and wait three years to try a tampon, and I went through sex Ed in fifth grade confused because my mom is a good religious woman (eye roll) and didn't want me to know what exactly sex involved. My best friend told me. Thanks mom.

Anyways; I've never tried a cup, but I'm thinking about it. I just want a general overview - the parts no one tells you. What exactly is the cup, how does it work, when do you change it, does it hurt (like a tampon), what brand is preferred, is almost sixteen too young, can it be during like swimming season, can you use it overnight? The stuff a package can't tell you and my mom certainly won't and takes wayyyy too much Google time when I can just put it here.

Thanks :)

Addition: the only thing that has been in my vagina are regular tampons by Kotex and their applicators but I don't even use them very often.