We all have to contend with our expectations... and the expectations of others. If you look at your own beliefs and attitudes, you'll probably see that you have a lot of ideas about how you SHOULD be, e.g. "I should have had a girlfriend by now", or "I should be taller", or whatever yours are. We compare ourselves to these ideas, and everybody has at least SOME areas where real life doesn't match up with their ideas of how it ought to be. You are unique: there is nobody else like you, never has been, and never will be. What is appropriate or normal for someone else isn't necessarily right for you. There's no right way you SHOULD be, no right height. Your job in life is to be yourself, and learning what that means takes significant effort... but you can bet it definitely does NOT mean fitting yourself into a mold given by ideas you absorbed from the culture. Does this mean you should NOT have a girlfriend? No, nor does it mean you SHOULD have a girlfriend. There is no "should" about it. When you meet someone you really care about, and you sense a connection with her, and you take the actions which express that connection (asking her out, spending time with her, etc.), then you will have a girlfriend. But there's no rule about when this should happen, nor is there any guarantee that it will. Just work on being yourself, and let life show you what's the next step each day.

I wish you luck. Because it's more important to find who YOU are and be that person than to be society's "man."