Before I met my husband, I was involved with two other people I met on-line who I met in person. While I think it's possible to love someone before you meet them in person, I think it is easy to fall into some traps that fool you into thinking you are in love.
I won't bother going into the second relationship, because it was casual, on the rebound, and never was going anywhere (and we didn't have any illusions that it was). The first one really devastated me. While I tried to present my best points, and minimize my bad ones, I didn't lie about who I was. Yet, after meeting him, he accused me of that. I came to realise that the sort of natural behaviour of "being on your best behaviour" sort of gets amplified on-line if you're not careful. He saw what he wanted to see, and his hopes for what I was like was reflected in how he filled in the gaps. We also didn't talk on the phone very much, and voice chat was not an option for him.
When I met my husband, I almost didn't get involved with him. Not only was I not looking for someone, my experience with the first guy made me think looking for love on-line was foolish. Sure, if you're careful you might meet some good friends or a person to have some fun with, but love's much too complicated to be sparked on-line.
Well, I know I loved my husband before we met in person. But, armed with the experience of my first internet dating disaster, I made sure he knew about everything. Plus we spent countless hours on the phone. Cheap international calling wasn't as cheap as it is now then, and he ran up a huge bill, but it was worth it. When we finally met in person, some 6 months after we started talking, the love was obviously there.
You are always going to have things you cannot find out about a person until you meet in person, but that's not that unlike the revelations you will find in conventional dating. Sometimes it works, sometimes it doesn't, and while on-line interactions might make it easy to create a fantasy in the other person or hide some aspects of yourself, it's not impossible to make things work, especially if you're careful and recognise the problems that can come up. But even if you're really, really sensitive to all of it, you still might end up with a failed relationship because that's sort of the nature of any sort of dating. It doesn't always reflect upon how you met and spent the first bit of your interactions.
Good luck, and enjoy this part of your relationship.