Why am I nervous around my girlfriend?

There may be many reasons for this! Maybe you are afraid of intimacy; sexual, emotional, or otherwise. Maybe you are afraid of being rejected, and not being loved for who you are. The sooner you learn to be 100% your self, the sooner you will be able to discover the value or lack thereof in the relationship. Never try and change yourself for another person. There is a pot for every lid, and you WILL find that person. Never settle!

Maybe you are afraid of doing something she might not like, afraid of losing her. Don't be; you are unique and special. :)

It could very well be that you are experiencing some doubt that you may not please her. This is completely normal. However if this isn't what you believe to be happening, then it could be (depending on how long you have been in the relationship of course) that you are just not yet used to being with her.

you probably really like her and it is a new relationship. I was the same When i got into a new relationship. It could also be the fact that you are nervous for a reason. Maybe you are scared of something?

Nervousness is sometimes okay when it's not fear.When you are in love being nervous is okay sometimes

This is so normal, it happens when you are so in love and you get a feeling that she will be your soulmate forever, it is not a bad thing, it happens to everyone

Just be yourself. If you act as if your some else then she will accept the guy your pretending to be in an effort to be like more by here you have to live out this illusion you created which cause a lot of stress and more lies . Let her see your true colors so there won't be any surprises in the future. Just take a breath and be slow and steady the world isn't moving as fast as you think and I'm sure her thoughts isn't fast either. So, perhaps your thinking too fast or thinking a head to avoid a situation.

Probably you nervous because you can lost her and this worry you a lot . So you can talk wiht her about this

thats something you need to think about for yourself, when is it that you feel nervous? what does she do that makes you feel nervous?

It could be because you don't feel secure around her; maybe you feel she is 'out of your league.' This feeling will surely pass at some point if you have a healthy relationship.