totally agree with enduro.
after 4 weeks, you will be more confident. i did a 1 week course but to be fair it hardly covered floor tiling and the setting out techniques were really basic. even the natural stone course was brief in comparison to what i have recently learned. the recent course i did was 3 weeks and i opted to do a week plumbing. there was a women there who was doing a city and guilds in plumbing and she said she learned more about plumbing in a week there, than what she had learned in the first 6 months of college.
apparently diamond is very comprhensive, so speak to kenny or phil from chase, just realised your from grimsby so that might be better. theres grants out there now that will pay 60% of the course fees!! get out there and grab them and learn the rest on here from all the lads!!
at your age you'll pick up quick because you have too. its hard to get a good timeserved
tiler to learn from so make your own luck to begin with and see what transpires. you could share work after your course and earn and learn ;0)
all the best mate
ed