@panopticonpeter,
I know that its probably not going to last, i never had that illusion. But i never had a boyfriend. I want my first one to be rememberable. Not 20 years older than me. Or is that too naieve?
I have the advantage of being closer to 42 than 19, and as senility has not set in prematurely I can remember being 19, which makes a comparison possible.
The first thing I notice is you don't seem to want a quick fling or a brief sexual affair. Even if you can't read the future, you at least want the possibility of a relationship to be within reach. You don't want to start out knowing for certain that it is just a short-term experience.
KaraBulut is right to say that it is too early to tell if he is even looking for the same thing. This is much less trouble to think about if you learn that he only wanted to ask you out, take you home, and then see someone else next weekend. But it is much too soon to assume that either.
If you spend a bit of time with him, these things will become much clearer, and you don't have to get further ahead that you would like to until those questions are answered.
So what could a relationship be like? You seem realistic about being in different places in your life. At 19 I had not yet settled the question of my sexual orientation, but that was very close, so let's assume I had that figured out. I had not finished my education and was not sure of my career. I lived with my parents. I had friends but no boyfriend obviously. I was not interested in "playing the field." I wanted to find someone I could connect with sexually but also someone I could love and build a life with. Some men are happy to sleep around for amusement until Mr. Right comes along, but I actually don't like people enough to get naked with them unless I was already in love. So, sometimes frustrated or lonely, but I preferred to be single to hooking up.
Anyway, at 38, I have found Mr. Right, and been together with him for 13 years, through mostly good times, usually excellent times. We've gone from struggling for every penny, saving while we shared an apartment to owning our own home and establishing careers, we've travelled together, got a dog, dealt with extended family, basically made the start of a nice life together.
A few things I have noticed: my life and our life is completely different than 12 years ago. But at least I feel like the same person. I knew who I was then and I didn't feel like I had to figure myself out before I could begin that journey. In that respect it makes no difference if I was 19 or 38, or probably 42 either.
But I also really enjoyed making that journey together with my guy. He is only a couple of years older, so we explored this time in our lives together, bought our first home together, got our first dog together, learned how to please each other and enjoy our sex life together.
It would be different with someone who may have already accomplished some of those things. Not necessarily worse. With a difference of 20 years, his experience could give you some advantages and make it easier to figure out some parts of your life. Some practical questions that a young man has to face when he establishes his life, as I did, are already answered. Instead of having to face these questions together, he has forged ahead and cleared a path, and made it easier for you.
This can free you to study, to think, to read, to follow a unique career path of your own, to do other things that also contribute to the relationship, things that he may never have had time to do when he was younger and which would be difficult for him to start now without you. It could be a very nice life.
Two things to consider:
First is the age difference itself:
If you have a relationship of 12 years, you will be 31 and he will be 54. When I was 31, I was living with my guy in our apartment and we had almost saved enough money to buy a house together. When I'm 54, I will be one year away from being able to retire, if I choose to accept early retirement with a reduced pension.
Second is the place you are at in your lives.
I hope he is further ahead than you are in many aspects of his life. If it seems very easy for your lives to fit together, I would ask "why?" What has he been doing for the last 20 years? Did his life get stuck when he was 19?
And then the most important thing:
When I met my guy, I had a million questions. And I didn't have to answer any of them to know. He was the right one. I could feel it. I could think it through too, and it all made sense. But I could anticipate that it could work almost instinctually. As they say in French:
l'amour à ses raisons que la raison ne connaît point.