Welcome.
You've got a bit of time before you could at the least join the Reserves and only if your parents let you. That being said, please take the time to read all the board rules and as many posts as you can before you start trying to be a member of the community. We are for the most part all adults and professionals, you are in good hands but it may/may not be an easy place for a young person to be part of.
If you have any specific questions regarding the Canadian Armed Forces, there are a bunch of us on here that have served and many are still serving. Take the time to find the answers yourself and if you can't find the answers; feel free to ask away.