Step-girlfriend needs advice - SD3
First post, so go easy on me... 
I'm "step-girlfriend" to an adorable 3-year old girl. Her dad, whom I've been dating almost a year, is a wonderful man and from what I can tell in my (admittedly limited) experience, a good dad as well. I love his daughter like she was my own, but it's very hard on me being thrust into a situation with such a young child because I don't know how to handle certain situations and feelings.
Generally speaking, she's a good kid. Obviously I've heard of the "Terrible Twoes" so I know that a lot of her misbehavior, grouchiness, acting out etc. has a lot to do with that. Her dad doesn't let her get away with anything unreasonable, he is fine with me disciplining her with things that are safety/common-sense/daddy-approved issues. So I think she's being raised rather well.
I know she likes me a decent amount, she always asks after me, sometimes she wants to play with me directly, or give me hugs/kisses/cuddles which makes me unbelievably happy. Whenever it's just she and I hanging out, she's well-behaved and cheerful.
But it breaks my heart when, for example, she falls and hurts herself, and when I go to comfort her, she screams "NO!!!" at me. I know she'd prefer her Daddy over me, but knowing it doesn't make it hurt any less. She's so hot-and-cold with me that I find myself thinking that if this behavior were coming from an adult, I'd have long ago given them a piece of my mind and taken my broken heart elsewhere. But of course she's a child and doesn't know, so what can I do...
I know it'll take time, and patience, and tolerance, and strength... but does anyone have any advice for how to handle these new situations and new feelings? I'll gladly take any recommended reading as well. I just feel like I need some help.
Be careful of getting too
Be careful of getting too attached until you're married. If you're considering marriage - or hoping - read as much as you can here as you'll need all the knowledge you can get. Remember even as a married step-mother you're powerless and will always be second fiddle to everyone including at times the kid.
Then think long and hard.
You will never be mom.. It
You will never be mom..
It took 5 years, and a heart breaking situtaion to find out for me, but I accept I will never be dad no matter if tehy call me daddy and the real father is gone for years at a time.
He will always be their father and mom will always be mom. So they will always want one of those two in times of need.
You can be a suragate at times, and they will love you dearly. They may respect you, and treat you like a parent but once in a while you will be reminded; usually innocently enough that you are not mom.
Its the contract we make when we decide to be a step parent.
From one step-girlfriend to
From one step-girlfriend to another, give it at least a couple more years (meaning keep your space, your time, your place) before you decide if this is a relationship you want to be in for the long haul. I have done this while reading through this forum thoroughly and I can't thank my lucky stars enough that I never moved in with my boyfriend and his kids.
She is only three now, so it sounds like she isn't fully aware of your place in her life. Is her bio mom heavily involved? If so, then that may make it much harder.
You won't know if this is something you want to be in until your thrust into a difficult situation. Like when SD sees you as a threat to "her" daddy, or when SD pits you and daddy against each other. This is not to put down your BF or your SD, I am simply saying you really need to tread this carefully. She wn't be three forever, and she will be a different person as she grows.
Enter with caution.