Is it really unrealistic for my teenage relationship to last?

I just really wanted to ask around because everyone keeps on saying “you guys won’t last” and I just feel like they are treating our relationship as a random fling purely because of our age. I don’t know if I’m naive and too young but I really don’t see why everyone chucks teenage relationships as something that won’t last when there’s pretty good proof it actually might? like I’m not talking abt the random teenage relationships where both partners don’t find it serious and break up within 3 months, but like genuine relationships where both partners take it seriously and have been together for 1+ years.

abt me personally, both me and my bf have been dating for almost a year. we are on really good terms, care about eachother and have learnt how to communicate quite well while already overcoming multiple pretty big conflicts (at least in my point of view. some conflicts: issues with time management as he is really busy with sports, and great distance for a prolonged time when I lived outside his city ) No matter how upset we were at each other, we always wanted to work things out and not give up on the relationship. He has never given me any reason to have distrust or think he cares about the relationship any less than me. in fact, he’s put in so much more effort as time went on and he makes me feel genuinely loved. Like looking around, he’s genuinely better than most “grown serious” relationships I’ve met (For example, he always cares about what makes me upset and works on it even if I’m being stupid or genuinely silly. I’ve heard so many stories where men say “you’re being dramatic”, and I feel so lucky to have someone who would never do that, even when I’m actually being dramatic and willing to admit it lol. Ofc this goes both ways, I always listen and work on things that makes him upset too, no matter what it is) I can genuinely see us finishing high school together and continuing on our relationship as we move into post secondary. we even had a serious talk about it already where we talked about what might happen, and agreed how we both want to continue our relationship without any doubts. I personally feel so lucky to have him, he’s so amazing, and our views towards our futures are quite in line with one another (like wanting kids in late 30’s once we are able to settle down for example).

Additionally, maybe my perception of “high school sweethearts” is a bit different from most because I actually know 6 diff couples who are highschool sweethearts (some are in 30s/40s as well) and are going strong. So I don’t see why it’s so unreasonable for people to see that we are taking our relationship seriously and not chuck it up immediately to “oh u guys will def break up“ just because of our age. Maybes you guys can explain it to me and change my mind? I just want to see things more from an older perspective that will actually explain this logic to me instead of just saying “you’ll understand when you’re older”