If you are new to the hobby, before giving advice, a few details about you are needed. First of all, where do you live, do you have a track and do you know any live steamers close to you? I would definitely not recommend a coal fired engine as your first engine. I also think that a coal conversion will cost as much again as the locomotive so unless you have deep pockets, think again. Run the Sammie in it's original form for starters and if you find live steam to your liking, THEN think about having it converted. Coal firing takes skill, patience, a fine touch and understanding of what is happening when you run.
By the way, giving your first name (at least) is a good way to start here.