Non-compete agreement in texas state

Hi,

My employer is a texas based asking me to sign on a “Non-compete agreement” . what are the pros and cons of this “Non-compete agreement”? what if i wont sign ? if i sign and break it?
can he proceed legally if i break the agreement? how would be the impact ? He is making money from me and asking me to sign the agreement. can anyone help me with any suggestions.

Thanks

Sampreeth