I love soloing... so much that half the time, I wish WoW were NOT online, and simply a questing/rp game I could play by myself, like Baldur's Gate or something. In fact, I used a free trial to download the game onto my mother's computer, so I could have 2 of my own characters on at the same time, so I could create a guild for my own characters without having to actually involve any other actual players (aside from the ones I got to sign the charter -- thankfully, without needing to pay for signatures). Sad, I know. And I did this on TWO servers, because I also like playing lots of different types of characters.
I'm going through some difficulties at present because a friend of mine recently convinced me to create a character on a server with another friend of his, and they are always leveling much faster than I do, so I'm always feeling like I have nothing to offer. (this isn't really true, just me feeling not so great). I want it to not matter how quickly I get to level x, just because I'm enjoying the actual game. But no, have to level up quickly, because otherwise, I won't be spending any time with them... which was the whole point. I just wish we could be soloing and talking about our efforts together instead of having to actually group (which also means me being high enough level to do so).
As it is, they only know about 2 of my characters, so at least, if I want to, I can play one of the other 4 by myself and not worry about being social. But then, I'm not leveling either of the characters they *do* know about, so...
The problem is that I actually do like grouping occasionally -- I just don't like to be the one that everyone else needs to help out. And I don't like to do it all the time.
I will say one thing as far as advice:
If you get into a decent group*, no one will hate you if you screw up. What they'll hate is if you don't learn from your mistakes, or even more important, think that because you're good at soloing that you're good at group playing, and thus don't listen when they give you advice/directions. Attitude is far more important than skill, at least, in my opinion (and I wouldn't want to be in a group full of skillful jerks). If you keep an open mind and learn from others and from your mistakes, you will get better at it.