Staying Safe and Secure

I’m hoping to get to spend some time in Europe with a friend next summer after graduation. He’s already 18, but I’ll still be a minor and I’m worried that my mom and dad won’t think it’s safe enough. I’ve read that hostels are great places to stay cheaply in a lot of countries; I wonder how I can find out which ones would be the least sketchy, if you know what I mean, so my parents will feel better about letting me go. Advice?