What should I do?

Dint let her take credit for your idea if it really makes a difference. Maybe you just let to let her know in a soft subtle way that your soft but not a fool. She best just watch it. You can always go and talk with the boss in private if need be??? Just dont be a pest. Hope I am understanding corrrectly.:)

What is it that you are discussing - a work project? Or is this a personal discussion while at work?

Based on some of your comments, I think it is a work project. Basically, you need to not be rolled over, but be more tactful than your colleague. A great way to do this is to make it seem like your idea is somehow linked to theirs...

"That's a WONDERFUL idea! And we can enhance it if we do........."

If you cannot tie your idea to theirs, acknowledge validity in what they say then introduce your idea...

"I can see why you feel ..... is the way to go. It has (A, B, and C) points going for it. However, if we consider (point D), another option would be ...."

Please do NOT try to talk over her. You are a quiet person - use that to your advantage. Look her straight in the eye, and don't let your voice get overly strident or emotional. This is especially important if you are discussing plans in front of others in a meeting. Maybe she has the deciding factor right now, but you want to be seen as the "grown up" by anyone above her who makes bigger decisions!

Overcoming overbearing co-workers takes work. But you DO have to work at it, or you will never get the acknowledgment you deserve. You CAN do it.

Don't focus on little things, just let her alone. Big things you should discuss with her, why not ask other collegue jion you, maybe she couldn't so crabby among so many people.

there are really those kind of colleagues. so just don't mind her and do your best on everything besides she's not the boss. impress the boss not her. but be careful with everything you do because she myt take it against you. good luck! and stay happy:)

there are lots of way for you to be heard my dear you just got to put a little effort on it. I cannot say something to you on what you should do you should be the one to think of an answer to your problem so that it would be worth in the end.