35 mi = about 60km EACH WAY = a lot for your first big ride (and 2nd ride on that bike/saddle) (and 2nd ride in years)

Allow at least 3 hours to get there, more to get back. You sure you want to do this going to a party? You'll be a bit sweaty and fairly tired. Your bum will be sore. If you are dehydrated, you will be vague and weirded-out for an hour or two. The main drinks will probably be soft drinks and alcohol, so rehydration will be a challenge.

It can be done, just be aware of what you're up against going from 0 to 7 to 70 in 2 days on a new bike.