I think if you want a 17" MBP, and you are willing to work for it yourself, then definitely go for it.
However, if you just need portability between your mom's house and your dad's house, you could even go with a Mac mini. Providing you have displays at both houses. Then you could keep all your files and everything on one Mac. Really, it doesn't seem like you want to do anything intensive... you just need a computer at both your mom and dad's houses. For $599, you can buy a Mac mini that really is nice. Then throw in four gigs of RAM, and a big hdd, and you're set.
But, if you really want a MBP, and you plan to start saving now, then maybe you will change your mind between now and the end of summer. Also, maybe you will find that something else will work better for you. Or maybe you will want it sooner, and will be willing to go with a prior generation for around a grand instead of a brand new model.
If you do buy the big brand new 17" MBP, you will have a solid investment that would probably last three to five good years. Especially with the ability to throw 8 GB of RAM down the road when it costs less. The ability to add a fast SSD in a few years, should keep it going fast. Snow Leopard should be out by the end of Summer. It would be a great goal to work forward to. A lesson learned that will last you a lifetime. Something earned is very sweet and educational.
Best wishes.