New Computer?

In the past few weeks, I've been considering getting a new computer, a laptop to be specific. It's not because my computer's not working, but that it's a desktop, so I can't bring it around with me to places if I want to edit or do my schoolwork. If I do, usually, my dad lets me take his computer laptop. Still, though it works for the essential needed apps like Google Chrome or Firefox, it lags and some times even crashes with my audio program, Adobe Audition.

I've decided I would like to get a MacBook air. But not the latest, since I found a previous model on amazon for $250 cheaper than the latest. But I wouldn't get it for just the price. Apple removed the USB port in the latest MacBook air, which would be a big issue since my mouse is USB, so I wouldn't be able to plug it into the computer. But the previous model does still have the USB port, so I could then use my mouse.