Pulled a knife in self defense, punishment in tx?

I received a felony charge because i was at a party and I got into an argument with some guy who started to push me so i pulled a knife on him to stop the fight, mind you the knife has a 2 inch blade and i need it to sharpen pencils in my drawing cl for school and I have also been jumped in this town before so it helps me to feel safe. the guy weighs atleast 300 lbs, not the fat kind either, he's pretty well built for a fat guy but still not the kind of guy I would like to fight. I only pulled the knfe to avoid fighting the guy and to stress the importance of him getting in his car and leaving. after telling him to get in his car and leave about 20 times because his ride was already waiting for him to get in the car as it was. He threatens to call the cops and i start to go home, he follows me down the street and again I tell him to go home and continue to walk home. The police eventually catch up to me on my way home, i dont feel like I've done anything wrong so I continue to run to my bike which was parked at a nearby store and the cops tackle me and I get charged with cl 2 felony of aggravated ault with a deadly weapon and a cl b misdemeanor of evading arrest. My bondsman said that i might be able to get the aggravated ault charge dismissed altogether but fears that I might not be so lucky with the evading arrest charge. ANY information at all on the subject would be extremely helpful, especially from people with experienced advice. Thank you.