I think you are going about this cycling thing in just the right way, learning about your and the bikes capabilities as your body becomes stronger. The experts on training tell us that as our bodies adapt to vigorous physical demands, muscles grow capillaries to carry the needed blood as well as getting stronger. Bones and connective tissue change to handle the loads. The trick seems to be to push the body just a bit but not too much early on. This process can take several years so there is no need to rush.