Receding or not?

I'm 18 years old and my hairline is looking like a "M" hairline right now, the very front is not receding but the sides are going back just a little. I was just wondering if it's just maturing or if I'm going to go bald. It doesn't look bad if my hair is long and my bains are long you can't tell but once I get a hair cut it's really noticable (to me at least!) if I let my hair down i can't tell but I like to have my bains up and I can tell that it is receding on the sides a bit. My father isn't bald he has long wavy hair but both my grandpa's are bald and my brother is starting to bald (he's crowning) i was just wondering if my hair is just going to continue receding? I know that the more I worry the worst it's probably gonna get...