hehe, I use to do a hell of a lot of CAD until Engineering board the hell out of me with all the equations etc.
If you want to try and get a CAD model in to a game, its possible BUT, its going to be **** as hell. Not **** in the normal sence, will look most likley very good, but **** in the seance its going to be soo unoptimized and going to have so many errors though the exporting and importing process that its going to lag the **** out of the game etc. Trust me I've been there and done that
The problem if you want to learn Modelling from being able to do CAD, you have got one tough road ahead of you, I've been down it
For me, being very much into dimension driven CAD, the hardest thing for me was simply getting my head around the differences between modelling and CAD, and what kind of work flow you have to use etc as they are pretty much the opposite and this can be very confusing.
With CAD, as I'm sure you know when your making something, you make something to be as accurate as possible, if its not accurate its worthless epically if your going to use it for any CAM etc.
With Game Modelling, like I said its the 100% opposite, instead of making something as accurate as possible, you need to only make something look right, it dosen't matter if its not accurate or not it just needs to look right. But ontop of that comes in something else, it needs to be optimized and needs to work with a game. Now when doing CAD, optimization doesn't even come into your head, you make something as accurate as possible, what ever the cost (poly wise etc). When doing game modelling, its has to always be on your mind, what is the best way to do this with it being the most optimized and for it to also look the best. If its not on your mind it will turn into a crappy model you can't use and will need to be scraped or fixed up. The other big difference, epically if you are into dimension driven CAD like I was, is that there is basically no dimensions to work with, you have basic things you can use but nothing like being able to just bring up a tool and get that lines excat length, what the angle is between thou 2 lines etc. Instead you need to rely just on coordinates etc.
For me it took what, probably 1 or 2 years to finally get my head round it and to be able to make a game model that could be used ingame. Now I can do some pretty good models, still not the best modeller in the world but I can make some pretty decent statics etc.
It might be much easier for you to get into Modelling than it was for me but I can tell you, it was really hard for me but once I got it, it clicked and now everything is easy
Hope that helps.