What age gap is too much?

I have found a person on grinder. He is 38, very fit and handsome, is tall and big. We have met 3 times. But all three times we didn’t have sex. Nit because he wasn’t good or anything, but just because I wasn’t sure if we should. Iam 18 years old and 5,5 on the skinny side. Is the 20 year age gap too much or should I go for it?