Most 20 year olds are less mature than a 30 yo. What I mean is that some 20 yo are less mature than a typical 20 yo. Some are more mature.

Op could be predatory, but it’s not predatory by virtue of age alone. there is also a big difference with, say, an 18yo. Or conversely a 23 yo. After 20, a 10 year gap is no big deal.

There are predatory relationships at all ages. From OPs description, this is not the relationship type they are looking for, as they themselves feel less mature. I’d say 25 to 18 is worse than 30 to 20. It’s not the age gap that matters but the maturity difference and power imbalance.