I just wonder this because I'm good at listening to people.

Well, I'm new to this too so I don't really know but I am a good listener as I can sit and listen to a person rant and rave for hours, but the problem for me lies when I think how much of that I actually heard. By the end of their story, I will likely remember about 1/3 of what they said.
When you're listening to someone, do their later referrences to it make you wonder what they are talking about, like "remember I told you..." and you' have NO idea what they are talking about?
I don't know if you're a student, but this becomes a huge problem in school.
My mind is often off in lala land but most people will tell you I am a great listener.
But if you mean you actually DO take in everything and can listen attently without distraction, then thats beyond me.

I'm usually very good at remembering what people said, anyway if it's something they're telling me about something and not that they're asking me to do things. I'm kind of imagining what they're telling me.

I've noticed though that sometimes; actually quite often, when my boyfriend tells me something (he's the person I talk most with) I get distracted by something and I miss a bit of what he's saying, but then I only ask him: "Wait, I missed a bit. What did you say about...?"

I've also noticed that I more easily lose track of a conversation when there're more people involved and I'm not really, really engaged in it.

I recently finished my studies at highschool level, although I'm 28. This is because I dropped out of highschool. I don't remember exactly how it was when I was younger, but recently I've had no problems listening in school.

Sometimes it's like I'm off in lala land and listening to someone in the same time.;)