You don't have to wear heels if you don't want to, especially now as there are so many pretty flat shoes around. I wear heels because I think they're pretty, and I enjoy being an extra couple of inches taller (and it makes me look thinner, which is always nice!). Practise walking around the house, but I really don't think walking in heels is as hard as people make it out to be! If you do start thinking about stilettos, boots are a good place to start - I find them much easier, as well as more comfortable, than sandal-type shoes.
As for the boots/dress combination, it can work, it depends on your boots and your dress!