Life In 19x19

Hi everyone!
This is a game I played against my PC (the easiest level possible) today.
I'm particularly interested in the moves 5-16. Was it the best tactic to defend and is Black in any way better off after 16 than White?

Thanks.

Everything but 7 looks reasonable. Extend after a crosscut. See http://senseis.xmp.net/?ExtendFromACrosscut

On a board that small, at move 16 the white influence is, IMHO, superior.

I really like the idea of playing 9x9 or 13x13 go when you are learning. Here are some comments (after the opening which Joaz already covered):

At move 18, if W plays hane at G5, it looks like W gets enough territory to win. Try playing out some simple continuations and see if you agree.

Move 19 is too thin, leaving a deadly cut. B should just push at G5 or jump to H4. W did cut, but then botched the continuation. The W atari at move 16 is a game-losing mistake. If W just extends to H7 without losing a liberty, the corner B stones will be captured.

Move 33 is not needed to capture the corner, so taking the large point E3 on the bottom would lead to a larger win.

Move 37 looks like a mis-click and would have lost points if W played atari at F2. Just playing F2 is correct for B.