I'm a 37 year old man who's completed roughly 9 grades worth of elementary and secondary education. I do have a GED and two years of community college but no degree. I enjoy a modicum of success, own a decent house in a good neighborhood (with excellent schools) with 12 years left on a single mortgage note. I have one car payment (and six cars - they're my hobby), two kids, bills out my ass, but no high-interest debt. I am married to a woman with a college degree but I out-earn her nearly 3 to 1 (I would say she's rapidly closing the gap and I suspect one-day will out-earn me). We have investments and savings totaling in the hundreds of thousands of dollars. I'd like to have 3 million between us in net worth before retirement but I suspect we will not get there.
All that probably sound like an endorsement, but honestly I think what I've done can't be repeated. I know of only one other person (he's 38, married, dual income, and no kids) that's managed to put together a similar level of achievement with a similar background. I think the door slammed shut right after my ass squeaked through. I also think had I done a better job applying myself when I was young and in the midst of my formal educations, that I would achieved much much more. I'm not complaining though, I've done extraordinarily well given the circumstances and educational background I have, and I happy with where my life is at and where it appears to be going.
I'd say the high-school diploma thing isn't a big a deal as some people make it out to be. If you're failing or stuck in a shitty high school (this was my problem, in part), dropping out and getting a GED isn't really likely to hurt you too much if you can manage going to college and getting a useful degree that applies well to a field of work you are interested in doing or alternately learning a useful skill and trade. Employers don't care about highschool if you have a college degree, hell you don't even have to put highschool on your resume. If you do go the skilled trade route, take some business classes. You'll reach a point where you realize working for a man who collects the profits while you make wages to the detriment of your physical health is not a path to financial security. You'll want to be the boss someday, and the business classes are what's going to enable you to do so.
However in your situation is sounds like you are on the cusp of graduating. Figure out this damn class, do whatever it takes to pass it. Don't fuck this up, not so close to the finish line. One of the keys to success in any field is a willingness to buckle down and do the hard work when the hard work demands doing. Right now you've got a load of hard work that needs doing. GET IT DONE.