5 Year Age Difference

Jasmine
 I am 17 years old and I have been talking to a guy that is 22. He is a great guy. He lives with his grandmother who is 70 years old and takes care of her. I have strong feelings for him. I am just curious of people's opinions on this. Nice or harsh. Also, if I do begin to date him, how should I tell my parents? Please leave responses!