Feeling like I don't deserve happiness

I'm pretty young (20), with a partner of 2 years (my family really didn't like him at first but things are getting a lot better). He and I have the same values, we think the same way about different personal and worldly topics, and we want the same things out of life at this point and into the future, which is much more than I can say for a lot of people my age, not to mention his sense of humor, selflessness, thoughtfulness, and the way I feel like I'm my best self when I'm around him. We're planning on getting married after I finish my undergraduate degree (2 years at the earliest), and our future goes from there (I've had type 1 diabetes for 15 years, and for that reason, I want to have my children before 30 so I don't risk health complications for either myself or my children).

I haven't started planning a wedding. No baby registry. None of that.

And for some reason everyone has something to say about how they think I should plan my future (I've heard "don't have kids too early", "wait to do A, B, or C", etc etc that come from both people close to me (but still don't quite understand where I'm at) and people who know nothing about myself, my health condition, or my relationship). I get that everyone wants what's best for me, but it's starting to feel like I don't deserve MY vision for my future someday in the future if everyone is attempting to jam their fingers into it and have a say in what I do with my mind, heart, and body, even my uterus. All of this despite me being a reasonable, thoughtful, practical person pursuing a degree at a great school and with plans for my future.

Just looking for some encouraging words to not give up and keep working on being who I want to be. It oftentimes causes me intense anxiety and depression, sometimes on alternating days. But I feel my absolute best when I make choices and plans for my future that I see best fit for myself and who/where I want to be down the line.