If the only definite income you have coming over the next year is $4k from coaching then you can't afford this laptop. If you happen to have car issues the day after buying the laptop are you going to be screwed? You will look pretty dumb if you have a $1500 laptop and no way to get to your coaching job.
If you still decide that you really want/need it (I just bought a 15" and like it a lot)...
1. Don't pay Apple to upgrade your RAM, as mentioned above. Search online and you can get it for 25-50% what Apple will charge.
2. Don't upgrade your internal hard drive. Just wait and get an external drive if you end up actually needing more space.
3. Wait to get Apple Care until your first year of warranty is about up. No point in giving Apple the money until then.
If you still decide that you really want/need it (I just bought a 15" and like it a lot)...
1. Don't pay Apple to upgrade your RAM, as mentioned above. Search online and you can get it for 25-50% what Apple will charge.
2. Don't upgrade your internal hard drive. Just wait and get an external drive if you end up actually needing more space.
3. Wait to get Apple Care until your first year of warranty is about up. No point in giving Apple the money until then.