Should I feel bad about this?

Anonymous
For the past couple of months, I (24M) have been talking to this girl (18F) I met on a Discord dating server. She randomly added me up one day, saying she's just "looking for friends" and we hit it off. A couple days pass by, and she proposes to me, telling me she's got a crush on me and would like to have a LDR with me. She was cute, and I was feeling lonely at the moment, so I said yes.

But here's where the trouble began. She was sweet and kind, sure, but a couple things about her was that she had said she had ADHD and she sucked at sexting or just texting in general. And I mean REAALLY badly at it. We would sex chat and exchange lewd pics of ourselves, and all she'd do for the most part was send emojis like "😳" or "😍" and that's about it. Then some days, she'd disappear and never talk for weeks. Also, I should mention that she was an atheist while I prefer settling down wirh someone who's the same religion as me, so there is that too.

So I decided to break things off with her for good a few days ago. She understood, but she seemed very sad about cutting things off, and now I feel bad. I was already feeling a bit hesitant about her situation (because I felt our age gap was massive) and the fact that she was just 18 and it would seem like she didn't know what to say for the most part. And even though a few of my friends would say that the age gap isn't that big, I still felt like I was taking advantage of her in some way. Any ideas?
Updates
4 mo
Thanks for all the answers. After careful consideration, I've finally come to the conclusion that I'll forget her and move on with my own life. She may be sad now, and I might be missing out on something special, but we had no real connection besides just sexting, and as @KrakenAttackin also put it, an LDR isn't a real relationship anyways. It's for the best.
Should I feel bad about this?
4 Opinion