Who tf do you invite if you’re hosting a party

I’ve had friends from work and from activities I do, but I don’t really know what the line is for “close enough to invite into my home”

Also, how do you manage the dynamic of people from different age groups? I’ve been hesitant to mix my new grad early 20s friends with my older, \~30 year old friends from my activities who have like… established careers and sense of self lol. Like I’d def feel weird if I were a 29 year old around a bunch of college new grads