When I started quilting in the late 70s there were very few quilt stores or classes. My mom never quilted but was an excellent seamstress so I learned the basics from her. I also took sewing in Home Economics in high school, (I don't think they offer that anymore, which is too bad).
The best thing I ever did was pursue a certificate in clothing design and construction from our local community college. The courses were well taught and comprehensive.
Sewing is sewing and learning the "right way" to do it makes a huge difference. Because of my education I know how to do everything from sketching out designs, making patterns, estimating materials, selecting fabric, layout, cutting accurately, sewing by hand and machine, (including beading and needle turn applique), fitting, and finishing.
Whenever anyone asks me which quilting classes to take I always tell them to take some sewing and clothing construction classes first. Even if you aren't interested in making clothing, it's the best way to develop a great sewing skill set.