alive mean that my brain is weak????....How do I improve tihs?

It is good that you initiate a convo!

The first big step is already taken. The next thing is to keep the conversation going on...

The biggest mistake people make is to talk crap, just to keep the convo going. This will make the girl feel uncomfortable.

The second mistake people make is that they think that they are the one that should do all the talkings. Girls have a mouth too, and they have lots to talk about.

The third mistake people make is that they don't listen! You don't just talk about yourself! Why would a girl listen to a guy's lifestory, while she just met this guy?? You react on what she tells you, and you turn this into a story that gives you DHV.

Keeping the conversation going is a skill. You can train this. In the beginning you should start with some canned material. But after a while you will feel the flow. And having a conversation will be part of your innergame.

Conversation is no monologue;
Conversation is not about changing facts;
Conversation is about creating a connection between you and the HB

Your obviously going about it the wrong way. After you have started the conversation you should be able to tell if she is attracted to you or not. The key is to ask her questions about herself. Females LOVE to talk about themselves. Ask her questions. This way roles are reversed and you are simply the listener. When she is talking to you DO NOT extend yourself towards her. Do not move position in your chair nor body and let her slouch towards you and into your ear. This is a prime body language tactic that shows you as the higher value person in the situation.