Do Sweet 16 parties have to be formal?

(San Jose, CA)

I've heard a lot about Sweet 16 parties and they seem pretty formal...Like $100 on a dress and this big dance with cool lights and a DJ with great food and no parents...I really have no idea.

I keep telling myself to wait until I'm 16 to visit other people's Sweet 16's but idk 2 years away seems very far...

Personally I've never thrown a party before either (just invited a few friends, like 2-3, and went to a restaurant then like a bowling alley or roller rink...Nothing special).

My parents aren't fans of spending a lot of money on me and my sister (but my parents go on $500 shopping sprees for my mom!!!!).

Haha sorry didn't mean to get too far with my personal life. Anyways, just wanted to know if it's an unwritten rule for sweet 16 to be a formal party.

Thanks! :)

-Mimi