How to get used to the bitter taste of beer?

I’m 21, I get invited to friendly little hang-outs and the good majority of my friends drink beer and bitter whisky. I’ve had beer before, a few, but I can never finish the bottle or the can. I have a sweet tooth and I’m not sure what to do, I want to like beer. I want to drink a cold one while watching football with my friends. I feel a bit out of it, I started by not putting any sugar in my expresso’s in the morning. But even then, the taste is completely different. Even red wine is too bitter for me, what can I do to improve my taste buds?