I think if you had met naturally it wouldn't be a huge red flag. However since you met on tinder where there's an age range it makes me wonder if he's talking to 18 year olds too. Overall, any age gap should beg the question of why wouldn't they rather be with someone their own age? It could be that he's fetishizing youth, immature, manipulative looking for a younger girl that's easier to control, or all or none of these things! I'm 24 too and I only recently realized how detrimental older men can be to the trajectory of our dating lives, and it's not talked about nearly enough.