Was I a bad kisser with my Girlfriend?

I am a good kisser and confident - still that doesn't mean every girl I kiss would be compatible. The best thing you can do is to kiss how you want to be kissed. If you sense a problem, ask her to kiss you how SHE wants to be kissed. That way you can see how maybe what you do is different than what she wants.

Also, always start slowly ... mouths closed .. let them open slowly as things progress ...

Just ask her. Other things could be in play. You might have had bad breath. She might have been self-conscious because she thought SHE had breath. Maybe she had to go to the ladies. Maybe she had something in the cooker.

If you're too shy to ask, which I suspect you are, follow her lead when kissing. Don't put your tongue further into her mouth than she puts hers into yours. [And obviously don't choke her with your tongue.] Try to swallow your spit before you snog her, if you can. Use breath spray or mints. When you brush your teeth, brush your tongue as well.

Sometimes a good snog gets a bloke in the mood and that can get old. It starts to feel like he's only doing it to get into bed.

Maybe she gets horny and wants a break for a few minutes,

When she pulls away just try and go back at it and see her reaction.

Well if you have to ask a question about it then.... But truthfuly she Probably just dosent wanna

Ask her

yep, sounds like it. Just ask her.

she might, ask her sometime when you're alone with her.