The risk is only in figuring out early that this isn't for you. You are only out your labor and the possible difference between the cost of the tail cone kit and what you can sell it for. At this point you are not building a plane, you are building a horizontal stabilizer. If that goes well and you feel confident, you will be building a vertical stabilizer. Then the rudder, elevators, and so on - until you end up with an entire airplane. It's a journey best taken in small steps. The steps get easier as the project progresses because of the steep learning curve. You don't even know now what you don't know, but the resources are readily available to help you along the way and you'll learn more than you could imagine. There are all sorts of unrelated benefits to what you'll gain in building an airplane. There's practically nothing you won't be able to fix in your house (if you want to). You will have all sorts of practical ways to demonstrate math, geometry, electricity, plumbing, etc to your kids/grand kids.
Good luck with your endeavor. There's no way to fail, even if you decide not to continue after your first part. If your initial goal is to see if this is for you and you find it isn't, you've succeeded. I built the wings on an RV14, and can tell you that it is the most refined kit Vans has produced to date. The accuracy of the parts is truly amazing.