Is their a certain age you can join?

Hi there! We welcome ages 13+ to our Planet. Members may join PF starting at the age of 13 with a parent/legal guardian's permission. Parent/legal guardian must be present with the minor during the sign-up process. Members between the ages of 13 and 15 must be accompanied by a parent or legal guardian when they work out. Members who are 16 or 17 years old must have a signed waiver from a parent or legal guardian on file.

I believe it's 18 to join but 14 as a guest

I think 18. I think am adult can bring a child as their guest with the black card. But I think it's 18 years old or older to join.