background of my relationship with her:

My dad and her have been dating since december of 2011, and  I met her the month of, I wasn't sure how I felt about my dad dating considering the gf before put her hands on me (that's a whole different story.) But I welcomed her anyway, and did my best to get along with her daughter (11f at the time). 

In February of that year, she and her daughter move in with my dad, at that point I haven't really spoken to her since I met her. So I don't know her at all really. 
There's been several occasions where I went out to eat with the three of them, and I was barely acknowledged. Except just from my dad.

She's a quiet woman and very reserved, has a good career and is well off. The only one she gets along quite well with my sister (out of all my siblings)

Okay, so last week, my dad invited me to go watch a movie with the three of us (him, my dads gf, and her daughter), and just as we were about to go she decides she doesn't want to instead. So me and my dad go anyway. 
On our drive to the theatre, my dad gets a text from her and I accidentally read the text and it said:

"Hey, I'm really disappointed in you, I thought it was going to be just us (her,her daughter and my dad.)" 
I honestly felt hurt by the message because I was the reason she didn't want to go. (her and her daughter saw the same movie but in the next town over)

I already know she doesn't like me (if I talk to her, she'll just nod her head and look away, or pretend like I'm not there if I'm with my dad) she goes into her room if I'm in the living room. 
 
Has anyone dealt with something like this? Am I just being a brat? Also, am I able to build a relationship with her?
user
How do I get my dad's gf to like me, that I've never met, so I can be on the same level as
assistant
background of my relationship with her:

My dad and her have been dating since december of 2011, and  I met her the month of, I wasn't sure how I felt about my dad dating considering the gf before put her hands on me (that's a whole different story.) But I welcomed her anyway, and did my best to get along with her daughter (11f at the time). 

In February of that year, she and her daughter move in with my dad, at that point I haven't really spoken to her since I met her. So I don't know her at all really. 
There's been several occasions where I went out to eat with the three of them, and I was barely acknowledged. Except just from my dad.

She's a quiet woman and very reserved, has a good career and is well off. The only one she gets along quite well with my sister (out of all my siblings)

Okay, so last week, my dad invited me to go watch a movie with the three of us (him, my dads gf, and her daughter), and just as we were about to go she decides she doesn't want to instead. So me and my dad go anyway. 
On our drive to the theatre, my dad gets a text from her and I accidentally read the text and it said:

"Hey, I'm really disappointed in you, I thought it was going to be just us (her,her daughter and my dad.)" 
I honestly felt hurt by the message because I was the reason she didn't want to go. (her and her daughter saw the same movie but in the next town over)

I already know she doesn't like me (if I talk to her, she'll just nod her head and look away, or pretend like I'm not there if I'm with my dad) she goes into her room if I'm in the living room. 
 
Has anyone dealt with something like this? Am I just being a brat? Also, am I able to build a relationship with her?
user
Dad's gf gets upset with me, says she thinks I'm not good enough, what do I do?
assistant