Is it OK for a 22 year old to date a 32 year old?

Yes. Age doesnt defy love, the person does. Just be careful though because sometimes older men tend to be more manipulative and controlling depending on what type of 32 year is he.

Is it weird for a 20 year old to date a 30-year-old?

20 year olds dont tend to date 30 year olds, and if they do, great. But chances are the older person has some issues you dont want influencing the younger one. Yes, but probably not much younger. A lot of maturing takes place during your 20s, and someone at that age is still evolving as a person.