Should I wait to get to Thailand before signing up for TEFL/CELTA?

Travellingteacher I entirely understand what you are saying. I was 31 when I started teaching here- 12 years ago now, and pretty much in the same position as you.. I didn't have a TEFL, but I was lucky enough to be taken on (and paid) during the long summer break- in that time I did a lot of my own research and study. My other half did an on-line tefl some years ago, and the work I had done on my own meant that the content of the course she did was very easy and straight forward to me, in fact it fell rather short of what I already knew. The things that I found hardest at first were actually class room management and just having the confidence to stand in front of all those students. The courses you are talking about will have practice teaching which I would imagine you will find useful (I certainly would have done).

For all that I would still advise people new to teaching EFL to have a read of Penny Ur's book - "A course in Language teaching- Practice and theory" which breaks down the whole thing very nicely- from process to content, core skills, grammar, lesson planning, testing, classroom management, syllabus and materials.and some more besides. (No I'm not on her payroll).

Anyway good luck.