if you have no experience whatsoever in tiling, basic DIY or another area of construction, then 13 days isn't enough experience to go out and work on peoples properties or be classed as 'self employed'
I'd say you should wait 3-6 months before you enter self employment if you fall into the above category ie no prior experience whatsoever and that depends on the ability of the individual as well??
in fact, i think the whole forum and the tiling world in general needs to stop saying 'they were' taught to tile by a course because they were not.
if you did 1 week, then you got a weeks worth of experience
if you did 13 days, then you got 13 days experience
if you did 4 weeks, then? you got 4 weeks experience.
what happened was, you did a period of time in a simulated setting, learned the basics THEN, came on here, worked with other tilers, read books, watched youtube vids, went on further trade related courses, maybe attended college, spent a few months/years practicing and improving and possibly done your NVQ's AND THEN you became a tiler...Surely, you have to be proficient before you go self employed and 13 days is not enough.
Nobody should ever give a tiling course the credit or the acknowledgment that they taught you to tile UNLESS you did a course and went straight out there and only ever used the methods they gave you and I doubt very much that's the case...A course is a starting point or addition of knowledge and course owners should not be telling people they are tilers or ready for self employment after 13 days with no other prior development.
this is not an attack on tiling courses, this is plain common sense that anybody can surely understand. if you are desperate/vulnerable or naive, people will always tell you what you want to hear won't they