Funny ad

I just saw an ad for an English school on a bus. It had a picture of a guy under which were the words:

I'm 15 now.
Guess
How old was I then?

Then, lower down, another picture, with the words:

That was me 10 years ago.

That's like that radio ad in the old days where the guy asks:

What time is the 10 o'clock news on?