I learned BASIC with line numbers and GOTO statements when I was 14 or so. There were two fancy control structures: FOR/NEXT loops and functions that could take one argument and return a value based on a simple expression. Later we got ON GOTO and ON GOSUB, which jumped to one of N line numbers given a computed index. I first saw real control structures, functions, and procedures in Pascal, took to them immediately, and never looked back.

None of it felt that difficult or confusing at the time; but then the programs were vastly simpler too.