Ill probably sound like an autist but here it goes

I'm terrible at being confident around my girlfriend. idk how i even grew the balls to ask her to be my girlfriend in the first place to be honest. My problem is just showing affection to her in public, it's very hard for me to kiss her, flirt etc with her around other people. In private its just fine.

What can i do to get over it? i always get urges to do it in public but when i try , it kinda just comes out quite or i never actually do it; and believe me, im not ashamed of her whatsoever, shes perfectly cute. So what do /adv/