<human>: Can you provide a brief rundown of the text in within 3 sentences?

I am a 23 year old college student, and my girlfriend [21] and I have been exclusively together for about three months. We had been seeing each other for about three months before becoming exclusive as well. All in all, she is great. We have similar personalities and hobbies, so there isn't much conflict. Most importantly, we are very comfortable around each other. Since we are similar in many ways, each of us can be ourselves, relax, and simply enjoy each other's companies. I've always been an odd one, but she has been, too. Therefore, I feel more comfortable with her than I have been with anyone including family members in my life.

I, however, have some doubts (for a lack of a better word). I do not feel the same way as I did with my first girlfriend. My ex and I dated for a few years, and it was a very positive experience. With my current girlfriend, I do not have the same electric feeling. Maybe it's because with my first girlfriend, everything was for the first time. I don't mean I do not care for my current girlfriend. I certainly do. I am very happy spending time with her and I miss her when I am not with her. It's just that I am not sure if the lack of ecstasy this early in our relationship that makes you tremble and smile from ear to ear is a bad sign for the future. Or, maybe I have just grown up just a little. 

Second, we have not had sex yet. Therefore, I am unsure about our sexual compatibility. I am physically attracted to her, and she is to me as well. Is the only way to find out our compatibility through the actual act itself?

Lastly, to the older/more experience Redditors, did you know early on if you and your SO were meant to last? For example, was it the sparks between you and your SO that indicated that it was "right" or was it more compatibility and comfort? Did you know that you and your long-term SO were good for each other early on or was it developed over time?

Please help this youngion out! I would love advice from all but advice from those older than me would be great too!
<bot>: Girlfriend is great. We get along well, and I can see myself with her in the future. However, there aren't any electrifying sparks.