Is this something I should be worried about?

[Jake]

My girlfriend and I have been in this relationship for about 3 months now and things are pretty great between us. It's like as perfect a relationship can be, because to say, we're quite similar.

Now, we knew nothing about each other 4 months ago. We were complete strangers. I had just heard her name once or twice because she's a really popular girl in her school. We are both 10th graders. We met over Facebook and we used to chat a lot because we soon found out that we had several overlapping areas of interest. Gradually we began to develop feelings towards each other and it should be noted that she expressed her feelings first. From there we progressed over time to stand where we stand today.

Now, from the time we entered into this relationship, we have both told each other everything about our daily lives. People know everything about us too. That means no secrets. But recently I found out some stuff about her that disturbs me somewhat. On her part, she claims that she has told me all about her past, but I don't know what to make of this.

We both have access to each other's social networking profiles.But I don't log in to her profile without her knowledge. A few days ago, she deliberately asked me to log into her profile to check out a funny conversation with one of her friends. This isn't something unusual for us. But then I started nosing around a bit. There had been rumors that she liked a guy from my school (months before we met), but she told me that she actually did not. Now, I stumbled across a conversation of hers with the guy from that time and there I saw that she had told the guy that she liked him and had also paid him a whole lot of compliments. She had also said that - "Do tell me if you like another girl but whatever the case may be, I'll always like you." Even the guy didn't confess to us, his mates, that he liked her. So, this took me aback a bit. That conversation was like 10 months ago. But all conversations after that looked pretty friend-like.

Now, I'll confess that this guy is really popular in our school and somewhat better in academics than me. So this leaves me feeling a bit insecure.

Again, two days back, she claimed that she had fallen off a bus and got hurt (nothing severe). Now, around seven in the evening, she told me that the doctor had told her to take rest and so she'd talk to me later. As I was (and am) suspicious of her, I logged in to her profile again just a minute later. There I saw her talking with a brother of hers (whom I later found out to be one of her family friends), presumably 5-6 years elder than her, and she asked whether he'd take her out for a drive then. He said yes and she replied that she was getting ready in 5 mins. That was the end of it. She texted me back at night saying that she had taken an hour-long rest and had then gone out for a while all on her own.

I didn't tell anything to her but I contacted a brother of mine, who knew her well and told him everything. He said that the bus thing evidently was false too and that the whole deal was just an attention-seeking maneuver. He told me not to worry about it and that it was a common trait at this age. He also said that she lied to me because according to him, she didn't want to tell me directly that she needed fresh air. This got me thinking about many other stuff she said that had happened to her, ranging from getting molested to slashing herself, but the thing is, I never saw a mark on her or any indication that she was into drugs.

I don't know what the hell is happening. She repeatedly confesses to loving me and I have also heard that she had told the same to many of her friends about me. I also got a report once that she had vociferously defended me, when one of her friends had said some bad stuff about me. I mean, all incidents are a huge paradox to me. Any tips on what I should do?