OP, your posting style aside I think people are reacting to the fact that you aren’t taking anyone’s points of view on board unless they chime with your own. You want validation, not potential (I stress, potential) realities.
I am 30 and DP is 15 years older than me. He is currently a very successful, well-dressed, active and interesting person. I would argue I am too! We match extremely well and I adore him.
But I know that he may well become ‘old’ before I do. He may fall ill, or need care. And after being together for so long, I won’t want to walk away - I will still love him, even if our currently wonderful quality of life declines. It’s easy to advise others to ‘just leave’ but that isn’t how people generally work.
Other smaller things: he has worked abroad; I haven’t. I may want to in 10 years (maybe? Who knows) at which point I’d be 40 and my DC would be at university. DP however would be 55 - what would happen then? It’s hard to plan for these things, but it’s at least worth having a conversation acknowledging them so it isn’t a complete shock if/when something related to different life stages happens.
All I would encourage you to do is hope for the best but understand it may not all be smooth sailing - no relationship is of course but there are very real things that crop up when you’re in an age gap relationship. And they don’t appear when your other half is still young and vibrant.
I sound like a cynic, I promise I’m not. But I know I’m dramatically different at 30 vs 20/21 or even 24, and I may yet change again before I’m 40! Just something to think about.