I'm pretty sure Rainbow Rowell's Fangirl is considered YA and the characters are in their first year of college, so I think the whole gap year thing is fine. Like others have said, it just depends on the tone and actual story you're telling and who you are telling it to. There are a bazillion YA books with drugs/sex/swearing/the works. There are definitely different categories within YA, as you'll notice in another recent post people discussing "clean" YA - free from the drugs and the sex and the swearing. Both types of YA books exist, it isn't one or the other. Definitely get out there and read more YA and more YA that is comparable to your manuscript. I also think it's really important that if you have beta readers, you make sure they are YA readers. A lot of people who don't read YA have many weird ideas about what YA is.