How old do you got to be to start going to planet fitness

I'm not sure, but I believe it's 18 yrs old & up. I would imagine because of insurance purposes

It's 13 with adult

First off, HELL YEAH THE WITCHER, second, I copied and pasted this from their site: "You can join PF starting at the age of 13 with a parent/legal guardian’s permission; they must be present with you during the sign-up process. Members between the ages of 13 and 15 must be accompanied by a parent or guardian when they work out. Members who are 16 or 17 years old must have a signed waiver from a parent or guardian on file. Please note that any PF Black Card® guests must be 18 years old with a valid ID, unless they’re accompanied by a parent or guardian."

I believe 13 accompanied by an adult

I honestly don't know. Sorry