I was in the same position as you last year when I had to choose my univesity destination.
I am 18 too and I study in Canada. As much as I love the aviation industry, my family doesn't really support this idea. They think it's more of a "dream" that can never come true and that this dream is too expensive. Being such a young adult, I don't have much money to afford the expensive training to complete a CPL. However, at the University of Western Ontario, it offers a program called BACS (Bachelor of Administrative and Commercial Studies) where you may study Aviation Management and get a degree when you graduate, and also complete your CPL during the 4 years of university studies. I applied for such program and got accepted. In the end, I didn't accept the offer. Why?
There are many factors to consider and many members in the forum have said it earlier already.
1. money. It just costs too much. Right now I only have 1/4 of the money to get a PPL and I am working hard to get the rest of the money. Getting a CPL costs a lot more. On top of that, I am already paying my own tuition fee and residence fee, etc. for my university studies.
2. education. and so you get a degree (well in your case, you are going off to training right the way), but the degree (the degree that I was mentioning about) is pretty useless other than working in the aviation industry. I need a back up. What if I can't get a job in this industry? I am not guaranteed to be employed by anyone after i graduate, even with a CPL, i need a lot of flying hours etc. I need a degree that is less specialized yet may benefit me in some other ways. That is, get a degree that is not aviation related.
3. For you, or for us, we are still young. We can get the CPL or whatever license you want later. Just take some time now, 3 to 4 years and get a university degre. This way, you are educated, and have a back up. After that, you may go for whatever you want (provided you have money).
4. Stability. You are not really stable until you are really employed by an airline.... so again.... having a degree may help you out here. As much as we want to be pilots, we also need money to keep up with our training and our everyday living. What if we don't get a job in the end right?
So in the end, I went to University of Toronto, and am now in there as their first year student, studying really hard for my Bachelor of Commerce. In the mean time, also trying to gather money for my PPL. My advise is, we are still young. After we graduate, we are only 21 years old. That's still young. We have lots of time to do things afterwards.
Good Luck.