If you're just using the hot tubs do you have to be 18, me and my friends would like to go but some of us our 17

you have to 13 to be able to use hot tubs

You have to 12+ ,I would call if I were you.

The answer is, yes, 12 and older, but one must be 18 or older to supervise the group

All guests must be 12 and up but at least one person in party must be 18+ to sign the liability release for the minors and be responsible for your group.

Yes you should be fine just remember this is a "whisper zone" so you'll just need to make sure everybody behaves accordingly.

You'll be ok

"Supervised children" 12 and older are allowed, so I think they'll be fine as long as you keep 'em in line. ;-)