First, I'm sorry that this hurts. But I'm going to lay a few hard things on you.

Your SD isn't your daughter. You may see her as biologically yours, but it sounds like she still has an active, or at least present, father. Or, at least a father that she grew up knowing. She likely isn't interested in having someone new step in and be her father. That has nothing to do with you personally. That has everything to do with having a father, and for reasons outside her control, he isn't available to her.

She has the right to not be as close to you as you want to be with her. She is not there to fulfill your wants to be a father. She is her own person, and so long as she is respectful of you, she is fulfilling her role as a stepdaughter. 

The other part of this is that you need to let Dad be part of the school discussions, so long as he is willing. School conferences and grade checks can be handled online. He can Skype with her to help with homework. He NEEDS to be involved as much as he physically can be, and it's not your place to take those things from him. Even if he doesn't want to be as actively involved as you would be, he needs to be able to act as dad as much as possible.

There may also be other reasons why SD doesn't want to have as close of a relationship with you. Differing personalities, marital squabbles, loyalty bind with Dad, personal views on stepfamilies - all of those could influence how she feels. But her feelings are her feelings, and she gets to dictate her relationship boundaries.

Lastly, if you want kids, get yourself into a position to have kids. If your wife doesn't want more, then you need to reconsider your marriage. 

I do understand where you are coming from. I'm struggling to get pregnant and did a head dive into being a parent to my SSs. But, I've had to learn to back off, especially as they entered the teen years. I am an aunt-parent hybrid now, and it works well. But, it certainly doesn't replace the want to have my own child and do all the things that a parent would do. I've had to accept the "loss" of my SSs as "my kids" by realizing that they were never "mine".

Yeah, hard as it is to hear, what Lieutenant Dad said is correct.

If you want to be that involved with her, do it - but do it knowing it's a gift, and not one that she has to reciprocate by seeing you as her father. She might someday, if you stick around. When she's older, she may recognize that you were the one there for her, and her father wasn't. Or she may end up hating you and blaming you for cutting her father out (even if it's not true). It's hard to say and you won't know for many years.

I'm not quite sure why you and your wife aren't ready to have a child after 6 years together, but I agree that if you want a child, you may need to leave this relationship.

I don't have the extensive stepparenting experience some on here do (much less even than you) and you didn't really give any details, but i do have experience with my biokids and as a biokid.

You say her father is uninvolved and you act like a father. As kids enter the teen years, sometimes they rebel against their parents and act like little sh!ts. I did, my sister did, and my biokids did. It was a phase and everyone outgrew it.

I guess the real issue here is, does your wife back you and give you full authority in your home? If it is normal teenage behavior, how you and your wife work together could make the difference between a short phase and juvenile delinquency. Also, i don't know how old you both are, but if you are still unsure at this point if you want biokids with her, that should be explored as well. 

If SDs feelings about you is your only problem then that's easy peasy. Just don't give a crap how she feels about you and continue living your own life with your wife. As long as she doesn't get in your face and disrespect you then it's all good. 

tried commenting but keeps sayin error :( 

I mean I think you have to accept the fact that she may not be as close to you as you'd like. Ultimately, she has the right to her feelings and boundaries. It doesn't sound like she is disrespectful to you. I am sure she does appreciate deep down what you do for her, but she has a father. 

I, like others that have commented, don't understand either what "not there yet" means in regards to you and your DW having a child. DH and I knew before we even got married that we weren't going to have a baby.

Is this timeline pushback on a child coming from her? Perhaps she doesn't want another child. That's a real honest discussion you need to have with her.