You've gotten very good advice. The only color you might like to add is beige. For piecing you need a color that will blend, rather than match. The point is that it doesn't show from the right side. I use Glide thread almost exclusively. My longarm loves it and I started to use it in my Janome, too. It's a strong polyester thread, very little lint (if any) and a beautiful array of colors. For piecing, stay away from rayon because it's not strong, although has a beautiful sheen, used more for embroidery.
Learning at 70 or otherwise is one of the most fun parts. It stretches your brain and makes you happy when you get good results. Be generous with yourself while you learn. If something isn't quite right, realize it's one more step out of the way to getting there. Let us know about your progress!