We couldn’t get her interested in us or engaged long enough to build a relationship with her. Social services (and us) were justifying the lack of engagement due to the adoption process which was being quite difficult, and we were always assuming after the next “step” she would be more engaged.
Presumably we’re talking about an infant here - around a year old? Who has been removed from her birth mum pretty much immediately?
At that age it’s not for her to “engage” with you, the work has to come from the parents/carers. While the complexities of the adoption process will have impacted you, she isn’t going to be aware of what the next step is and when it passes - she isn’t holding her breath in the way you are because she doesn’t have the cognitive capacity to know the process.
She’s a baby, she doesn’t build a relationship with you, you build a relationship with her and at that age it’s all the drudgery of feeding, cleaning, changing, bathing, consistently responding to her needs that builds relationship (and that fosters attachment). I’m surprised the social worker hasn’t explained this. She is a traumatised infant, it’s going to take a lot of time for her to feel safe and secure.
You’re talking in a way that suggests she’s purposely not engaging - she’s engaging in the way she knows how. Her whole life so far has been with you, and while I know you don’t think she has a bond with you disrupting will have a significant impact on her. That’s not to say don’t do it but really consider your reasoning here.
It’s far too soon to be thinking about ASD, she will have some developmental set backs depending on how birth mum was during pregnancy, just the separation from everything familiar to her while in the womb will have an impact. Also consider that you didn’t have the pre-birth experience of carrying her, feeling her move inside you, adapting your lifestyle to accommodate pregnancy - all of those things start a bond well before she arrives, and pregnancy hormones help that process along and even then it’s not uncommon for birth mums to have to work at loving their baby. You’re coming at it from a standing start without those experiences, your life has been turned on its head and you’ve had the stress of the foster to adopt process which is very tricky at the best of times. Of course you’re going to protect yourself emotionally, which will impact your ability to truly give yourself to loving this baby.
Before you make a decision, have a think about what you thought this time would be like, and how it’s been different for you. Try not to centre that on how your baby has been but everything that’s been going on for you and what you wish had been different. Watch her sleeping, look up theraplay games you can play, do lots of skin to skin contact - swimming is really good for that. Give yourself a chance with her.
I think people often view adopting a new born as an easier option because the baby only knows life with them, and who doesn’t love a squishy baby but actually it’s much, much harder because they are so very dependent, you’re sleep deprived, don’t have bonding hormones and everyone is telling you how lucky you are, when your life feels like a grenade has gone off.
What you’re describing sounds very, very normal. Now the legal process is done you can open your heart more safely, you don’t need to apply for the adoption order any time soon, give yourself time.