I wish AH made Alex grow with us instead of remaining 14 through out the series. I started these books when I was in 6th grade, I read Crocodile Tears during 11th grade and it seems I've outgrown the series

Anyway, Alex being 14 and having all of that stuff happen to him in one year is super far-fetched. I love AH's writing, but it would've been nice if Alex grew up with us like Harry Potter and the gang.
Now I'm trying to scrounge up AH's adult novels. The Killing Joke is my favorite.
While I did like growing up with Harry Potter, I don't think it is necessary for Alex to have grown up. I've been reading these books since 3rd or fourth grade and I read Crocodile Tears as a Freshman in college and still really enjoyed it. I actually think it would be less realistic and exciting if these events were spread out across years because in real life spies are sent to do jobs constantly. They don't just work for a few weeks out of the year or something. It's just like any other job, you work constantly and you may have a project for a few weeks but when you are finished with your project you get a new one.
As for Alex becoming 15, etc. I suggest everyone reads Anthony's latest blog post if you haven't already.