Leading should not be the main reason to climb, unless you're some sort of macho man trying to impress. I've seen a great number of young blokes enthusiastically get into leading; scare themselves silly; then drop out of climbing altogether. I climbed indoors TR for 10 years before my first outdoor climb. I absolutely loved indoors but now I love outdoor climbing even more. If you are leading slabs and vertical walls, at some point you will seriously injure yourself. Once you are an excellent climber and climbing mainly overhangs, you will find leading much safer.