Terrible Two's?

Savannah is getting so big I can't believe it! I fall more and more in love with her watching the new things she does everyday but she is also learning her boundaries with me. With Daddy, there is no boundaries, she does as she's told instantly. But for me, she grins and looks me in the eye just waiting to see what I'll do next. I remember I did the same thing to my mom thinking it was funny to see her mad and never felt threatened by her when Dad wasn't around. Now I'm on the other end of things. (Yep, mom and dad always told us kids this would happen!) Sure she'll pick up her toys AFTER she gets out of timeout, but to do it when I've asked her the first time has yet to happen. So far she has never taken me seriously but that needs to change. Just last night, she asked me to get her blocks down, and I told her, "No. Since you won't pick them up when you're done with them, you can't play with them." I wonder if any of that sank in. Any helpful hints on mommy authority vs daddy's?