I bought one package each of 10s, 11 and 12s when I first started hand quilting ( a long time ago) and I still have needles in each size. Using the smallest needle you are comfortable with is helpful in learning to make very small, even stitches. Honestly, in my experience, consistent size and spacing is more important than tiny stitches, so just start out trying to be consistent, then work on honing the size.
RST