That's great! I'm glad it's going so well.

It might help to try getting her to sit first then from there down, it's usually much easier. Going from standing to down is much more difficult to teach until they know what "Down" is. Use some food to get her down and say "Down". Once she's there, step on the leash close to the collar (not so close that it pulls unless she tries to get up). Only hold for a couple of seconds initially then release and praise, slowly work your way up to longer times.