Maybe wait a little. Most 17 yr-olds are at a different emotional and cognitive maturity level than most 22 yr-olds, but a few 17 & 22 yr-olds could match up (that's one issue). Another issue is the legality of the dating. The law sees a 17 yr-old as a child, so a 22 yr-old may want to wait until the 17 yr-old is an adult. Also, at 17, one is finishing high school (much different from being a 22 yr-old college grad).
Hard to say. You don't mention gender and or define "date". Males emotional journey to adulthood takes longer than females, so there can be some similarities in their emotional level with this age difference.If the "date" involves any sexual contact, various states may or may not consider it illegal.Those with a true bond can wait a few years to see if the link remains strong.In 3-5 yrs , few would question it.
22. And 17 years? I don' think it is legal , she is. Teenager and u r considered adult.So i advice u not to do it.