F19 / M28. Feeling unwell and insecure in my relationship because he's so much older than me. I don't know what to do?

I'm a woman, 19 years old, and my boyfriend is a 28 year old man. He treats me well and acts as though he loves me. But I feel like I'm probably too young and he's way too casual about my age, like it doesn't bother him at all. We met a year ago.

I'm worried that maybe he just has a thing for women my age or whatever, because he's made some comments (not really anything specific, just implying that he doesn't care about my age or our age gap.)

He messaged me a year ago online knowing I was 18.

I'm starting to feel kinda grossed out like maybe he's a creep or something, I don't know. I don't really know how I should feel.

Sometimes I feel like maybe he's taking advantage of me and manipulating me because I'm "young." That's the context of when he first messaged me, but it was consensual on my end and a sexual thing. But I was also high so I don't know.

I've met him in person twice now. First time he came down and essentially lived with me for 3 months. The second time he only came down for a week and that was relatively recent.

He was the oldest man I've ever dated and at first him being so much older than me was a turn on and intriguing, but now that it's so serious and we're committed I don't know.

I also get anxieties/worries that when I'm older he'll leave me or just cheat on me for a younger woman, if this is really just his type.

I don't feel comfortable being with someone that just likes my age.

I posted this also in the age-gap subreddit and the first response I got was from a 33 year old woman saying "I’m not sure what the issue is if everything has been consensual and he hasn’t given you any reasons not to trust him. You are an empowered adult and can make choices for yourself !!"

Now I realize that sub probably isn't a very unbiased source, and I really need unbiased opinions on this.

Sorry for talking so much, I'm partially venting here because I don't have anyone else to talk about it with.

Any advice or support would be helpful. Please don't be rude because I'm really struggling right now. And please don't send me any requests from this post, I'm not looking for anything.