Parents?

I've been seeing a guy that's about 4 years older than me, we really like each other and became exclusive recently. I would love to introduce him to my parents, but I'm not sure how they'll feel about the age gap because their age gap is only a few months. How do you ladies suggest I go about talking to my parents about the age gap? I'm 17 and he's 21, but it's completely legal where we live because the age of consent is 16 here. Thanks so much!!!