As long as you are willing to learn you will get the hang of things. Everyone says not to pick up a nonworking machine for a first pin, but that is exactly what I did. I was always mechanically inclined and enjoy learning how things work. If you have no mechanical skills, pick something up that is working. Everytime something breaks, post a thread and learn a skill. Eventually you will know how it all works.
I suggest getting someone who is into the hobby to go with you on your first purchase. Many helpful people right here on pinside who would be willing to help someone new get their feet wet.