It is not bad once you do it, but it is not really that easy for someone with no guidance and you need tools that many may not have (like a chalk line, tile saw/grinder). You also need to mix mortar and grout which can be frustrating and messy for someone who is new.
That said I would hang around and watch. You can pickup a ton of knowledge by just watching. I would let the guy know that you are interested in learning and not hawking over his work from the start. Most guys are cool with that if you are not overbearing.