So I am going to sign up for a 15 mile race 7 months from now. The entire race is at high altitude and a lots of elevation gain. I've only done 5ks before and I always have a lot of trouble with hills. I'm wondering what level of training I'm going to need to do to get better at hills, trails, and altitude. So far my road record for distance is 6mi and my trail record is 4mi.
Am I making a mistake or not (I'm doing this either way)?
I remember one time I was playing WoW in the Burning Crusade xpac. I asked the forums if I was ready for Serpentshrine Cavern while having a piece of gear from that very raid. You have some idea of what it's like to do a race and you can make a very rational prediction for what a 15 mile race is going to be like.
You picked a very reasonable goal that will require planning, training, discipline, and execution. For my money that's an exciting goal and the kind of thing you can really sink your teeth into.