Hi everyone, I am new to this forum and I need assistance of any more experienced players out there.
I just finished reading The Mystery Method and The Pick-Up Artist, so I've just started to learn the rules of the Game and my game is still very unpolished. I need help because I might have upset my target and I don't know the right way to fix it.

I'll get to the point right away. I have been gaming a girl that works with me, she is the new girl at work so it was easy to open her since she is bound to meet new people at work. Anyway, I had to find a substitute to work for me today because I had MMA practice, and so I asked her a few days ago if she could cover my shift. She said she had a lot of studying and papers to write, but she knows how important the practice is since her brother does it as well and so she took my shift.. However, later on that same day, my manager offered a higher position that would get paid more, and he asked me to come to work today after the shift that the girl had covered. I obviously need more money because I have bills to pay, and so I accepted.
So today, I had to skip one part of MMA practice (it is split in 3 practices, BJJ, Muay Thai, and Boxing & Conditioning) so I could go to work. When I got to work the girl was just leaving and she saw me, and she asked me if I wasn't supposed to be at practice. I was running late and I was in a hurry so I told her that I had skipped practice. She said that if she knew I would have skipped practice she wouldn't have covered my shift because she could have been studying instead, I told her I was going to be late for work and I quickly walked away.
She seemed very upset and her ex-boyfriend was a dick that made her give up a lot for him and she hated him for that, and she had told me that I was the opposite of him. I need help on how to possibly fix this.

This is what I had in mind, remember I am new to the Game.
(When me and her are at the same place)
Me: You didn't let me explain why I was at work the other day.
(I explain that I was offered a new position and that I had to skip one part of practice)
(And before she says anything I say)
Me: I will teach you what I learned so that you can beat the shit out of any girls that are hitting on your boys. (I should mention her boys so that makes her think that I am not chasing her?)

I'll then carry on the conversation and eventually tell her that I need to get coffee and ask her to keep me company, would that seem like I'm chasing her? If this is not right, how should I do it?

Thanks for any help available.