TO23 saidI actually have a "friend" (not much of one lately) in his 20's, and he's dating a guy 7 years younger than him, and he's still a teenager, and it disturbs me quite a bit...we're actually not as close anymore because of it, but not because of the age difference per say, but that combined with the fact that my friend is immature and is notorious for always dating younger guys, due to it being easier for him to get a date with them. If you're dating someone younger who is mature, and you're immature, i find that a bit appalling; capitalizing off of a younger person's choice to take on more weight of maturity, when you're older and have no ability to be mature or wise to me is unfair. Your brain is pretty much finished forming at age 20. The age of 20 is not all that impressionable, you are no longer a teenager. You are an adult. By the time you turn 20, your body has done almost all of its growing and developing. I don't buy all this latest bullshit that the mind doesn't finish forming until around 24 or 25 years of age. That is all just a glorified coverup for poor upbringing that has become commonplace these days.
To the OP, as long as you're mature, and you have good intentions, as well as an ability to not take advantage of his age in some matters, you're fine. You seem experienced enough that your only motive behind the relationship is out of solidarity, not a back page agenda to increase your ego, or lack of confidence, like some predators do.
Even though 7 years isn't really much, the age of 20 is still impressionable, and your brain is not finished forming yet, so I respect you a lot for posting your question; most gay guys I know don't give a fuck about anything you mentioned.
Whether it's finished forming or not, at age 20, our social system and education system still pretty much has you, and there has been little time for you to develop a sense of self outside of a major institution of socialization, which is necessary for you to be able to effectively establish what you need in another person, and for yourself. Your own conscious self is more powerful than a lot of the tiny calibrations that are occurring post adolescence, but the fact of the matter is that at 20 years old you're still a fucking kid, sorry. I was incredibly intelligent at age 18 to 20, and from those years to what I am now at 23, I might as well have been a complete idiot with the decisions I made.
Also if you supported your theory with something more than a conspiratorially driven criticism, I would maybe say your statement has a bit more credibility. On top of that, your frontal cortex which is responsible for making decisions, legit finishes forming last, and to say that everyone has theirs finished at around 20 and not 25 for some, when some people begin puberty at 11, while others start at 16 or even later, just doesn't even make any rational sense on an empirical standpoint, unless you have some kind of ground breaking evidence to support it.