The fundamentals of drawing and design are not technical skill that are so hard they couldn’t be learned by someone with half a decent hand-eye coordination within the span of six semesters or much less, assuming regular and diligent practice.
Using bases is fine as a crutch but eventually you may want to try swimming without the floaters or riding a bike without the training wheels, the sooner the better.
Drawing is a motor skill most of all–and that means muscles, nerves and bones–and like any and all physical exercises you should try to keep yourself challenged, but never overworked, to stimulate growth. Listen to your body, rest, eat well, and take appropriate breaks. Avoid burnouts as much as possible.