I'm honestly not trying to be snarky here. But if you're really acting the way you describe here (poking holes in what your mom's friend thinks about Celine Dion, saying "tell it to your therapist, this is completely irrelevant to me"), then you are going to do a lot of damage to your personal and professional reputation. If I heard a 1L talking like that, I wouldn't think they're confident and analytical. I'd think they're an arrogant prick. I'd avoid them. And if given the choice to work with them, I'd be concerned that they lack the basic social skills to function in an office environment and navigate a client relationship.
It took me over 8 months as I started with a really low diagnostic (low 150's). I was working full-time so I could only do about 4 hours of studying during the week and another 5-7 hours over the weekend. I think it would have taken less time if I had the option to study full-time.
I did the online course from 7Sage. What helped my score improve was doing timed practice tests and then going over questions that gave me difficulties. I would write explanations on why I thought the right answer was right and why the four remaining answers were wrong. I would do this before I even looked at the answer key to develop my reasoning skills and intuition. If I was wrong, I would revise my explanation and write down what my flawed assumption was so that I could learn from it. For logic games, I just kept doing them over and over again until I got the answers within the set time.
I think it's good that you're giving yourself a lot of time to study. I would aim for the December test. If you need to retake, you still have one more shot. Keep in mind U of A averages your LSAT score. All the other schools take your highest.
If you're asking whether you're making a huge mistake to go into law school because of the future debt that's a cost benefit analysis you'll have to do for yourself - but is that your question? It sounds like you're asking whether $75K is a manageable amount of debt and I guess my answer would be if you have an option to make it lower why aren't you taking it? I mean if you're going to go to law school regardless, and you have no other options, then $75K is manageable by default.