I completely agree with you @Tulip.
Go back and pay close attention to the ‘I Dreamed a Dream’ scene and pay close attention to the lyrics and who is singing what lines. It’s clear that the song has two different meanings to both Rachel and Shelby.
For Rachel this means her little fantasy of having her mom in her life is going to come true and they will live happily ever after - “And still I dreamed she’ll come to me and we will live the years together.” Rachel is very naive and looks at the world how she wants to see it. For the most part she doesn’t see things with too much realism she sees it as a play or a movie where for the most part things have a happy ending.
For Shelby she thought this was her chance of finally having something to live for. From hearing little snippets of what Shelby explained her life to be, we can all get that her life sucks. She doesn’t have that big of a support system or none at all. She had to become a surrogate in order to try to fulfill her dream of going to New York, so you can probably guess that her parents weren’t that supportive. Shelby thought that ‘trying to get Rachel back’ would mean that what ever void in her life would be filled, but obviously it wasn’t there is nothing there between them.
"I had a dream my life would be
So different from this hell I’m living
So different now from what it seemed
Now life has killed the dream I dreamed.”
Shelby knows that she made a mistake which is why she tried to do something so it work for the both of them. She explained to Rachel that she was wrong and she may be her mom but she isn’t her mother. And Rachel even agreed that she didn’t feel anything to Shelby either. Shelby even sings with Rachel - which is something Rachel has been wanting to do for a long time - and she leaves Rachel with a gift (the cup and the costume if you want to get technical.). The Shelby proceeds to say lets’ just appreciate each other from a far, in meaning right now is not our times and I’m sorry for interrupting your life, but maybe in the future we can for something, but for right now just focus on something else and continue on to living your life. So please tell me where in there did Shelby just abandon Rachel and basically say i don’t want anything to do with you?
Even if Shelby and Rachel were to form something Shelby still have every right to adopt a baby, get married or do what ever because it’s her life and she can do as she pleases. Just because Shelby and Rachel meet doesn’t mean Shelby has to change her life to suit a teenager whom you know nothing about.