I went on my first tour last year....alone. Buffalo, NY to about Louisville, KY. I was supposed to go to Austin, but had a little mental breakdown on the way (I was only 19...not that I'm that much older now) and ended up calling my mom who drove 600 miles to pick me up on a street corner in Indiana. I don't regret anything I did though, and I think that's the biggest part. Sometimes, even if you're frightened, you just have to go. If it doesn't work out, it doesn't work out. You'll kick yourself if you don't at least give it a try, trust me

edit: as far as talking to your mom about it.... my family freaked out on me (my grandma told me she would never talk to me again...we're still very close!). They'll be scared for you too, sure, but just reassure them. The best way to do that confidently is to make sure you are sure of yourself too, and that doesn't mean you can't be nervous.

The hardest part to doing anything is starting it, like Northwestrider said. I've always found that to be true, whether it's actually putting on your shoes to go for a long run or just getting on your bike and pedaling to get out of the city. What would be the point in getting out of bed if there was nothing challenging awaiting you?