Being an overeducated engineer, I have a different enough background than you that I’m talking out my ass, but a couple thoughts:
– Being competitive in law school will be awfully hard unless your family is willing to full support you on the home front. Your competition may well have a lot fewer distractions than you.
– Even if you get a $100-150k job after you graduate, consider what it costs. My lawyer friends work 20 more hours a week than I do, and have $100k more loans than I do. They’re welcome to a higher salary.
– Sales is a fine jumping off point to start a more ambitious job, especially at a start-up. You might consider the next such offer, and talk to the principals about your desire to do more than sales. In many of the startups I’ve seen, the initial sales guy becomes the CFO pretty fast. Any small company benefits from someone who can wear many hats.
– If you do go to law school, tailor your education to enhance something you’re already good at, maybe sales. Generic lawyers ARE a dime a dozen, don’t be generic.
– Learn math at some point, just to prove to yourself that you can do it. If hormone-addled teenagers can do it, it can’t be that hard.