NIkole ~ I've got to agree that this is going to be hard. I know you want to go, but being around alcohol in early sobriety (IF you're new) is going to be tough.
I know you feel you have to go for your Dad. One thing to consider is -- do you want to disappoint your Dad if you DRINK?? If you had a drink, your Dad would be really heartbroken, wouldn't he? After all your work to get sober, wouldn't that really hurt him?
Will there be people there who DON'T drink? How about hanging with them? Even if you don't particularly like them, they're SAFE. Stay around them for as long as you're there -- and you don't have to stay long. Tell Dad that it's too stressful for you with the alcohol there, and make a hasty leave when you begin to feel you're going to lose it. It doesn't matter if you haven't been there long, just so you put in an appearance.
The best yet, would probably be just not to go at all -- explain to Dad earlier.
I wish you the very best dear Nikole. God bless & my prayers are with you. Big hugs, Lee