Attitude much?

Wow does my LG have an attitude! A few weeks ago she locked her bedroom door so I took the knob off, she was so upset but I told her I would if she locked it again so I had to follow through and yesterday she attempted to barricade me out of her room and she got a spanking for that one. She stomps her feet and yells and tells me that she hates me. She is getting so big and such a mind of her own. On Mothers day we took her training wheels off, She was riding her bike everyday but now she hasn't touched it lol. Not that the weather has been very amicable to bike riding anyway. So her misbehavior has gotten out of hand and I have had to bite my cheek and be firm with her or else end up very sad at the end of the day.