Sorry, That Degree's Expired

I'm 20 years old, I've graduated high school. I want to go to college, and I will, but I have no idea what I want to do!
I know I'm not the only one, but I feel like such an idle loser for not already being in college when my friends are going into their third years while I haven't even applied. Is this normal? Why am I so scared to start school?
Right now, I want to go into Interior Design because it's fun, creative and I'm good at it. But I'm really good at putting together rooms on the Sims, but school requires me to draw everything, and I'm not a very practised artist. I feel like if I go to school before I heavily improve my drawing speed and quality, I'll just get run over by all these fantastic designers who have a one-up on me because they can draw.
Another weird reason why I'm putting off school; I'm scared of how much time out of my twenties it will take. I need at least 5 years to become a licenced Interior Designer, and by that time I want to start having a family. I feel like I'm gonna end up spending 4-7 years in school only to graduate, have kids and then stay at home. What's the point of getting a degree if you're not even sure if you want to start working until your kids are in school? Would it make my degree less relevant if I don't start my career until years and years after my graduation? It would, however, save time if I got my degree now, rather than waiting until later and having to spend more years not making money when there are kids at home. I'm just having a really hard time finding any information on whether or not there's an expiry date on an unused degree. I don't want to graduate and then be told by the time I'm ready to work that there have been a bunch of changes and my license to design is no longer eligible, and then I'll just have to go back to school anyways. I don't know whether or not I'll get any answer at all, but I'm just putting it out there. I'm sure there are others who are in the same situation as I am; there has to be! ...right?