Age of consent veries a lot from country-to-country but generally 3 years isn't an issue.

There are some pretty huge differences in the needs and interrests of a 17 year old from a 14 year old. I'd strongly suggest you two hang out as friends for a while and see if you feel like you're both connecting, if you can go out and do things withouth arguments, if you get along with their friends, or if you have as much in common as you think. Give it about 5 solid days of hanging out togather before you decide if they're right for you.