It’s wonderful that you have a big heart and you have a lot of love to give, but it’s probably best if you meet this girl and spend a little time with her before you tell her you love her.
The internet is a terrific way to meet people and connect and communicate. But when it comes to personal relationships the internet shouldn’t be the sole means of communication. In fact, nothing beats person to person. The problem with professing your love to someone who lives too far away to get together with in person, is that you may mistake your internet relationship for a real life one.
You sound like you’re young and have a lot of life ahead of you, so why don’t you try and meet this girl and spend some time together first, before you tell her that you love her. There’s no way she’ll think it’s creepy if you do it in person.