I have a 4 year old myself, with my egg cracking about halfway through the pregnancy. In my experience, there has been a bit of adjustment, but at the same time it hasn't made much of a difference honestly.
At the end of the day, just being a good parent, gender notwithstanding, is all that you need to be. My daughter sees both of her parents as "mom," but we try to both cover the breadth of roles that are traditionally seen as paternal, as well as maternal.
There might be some weirdness when it comes to interaction with other parents, depending on how you pass, whether you're out to the general public, etc., but we've honestly had more difficulty being "the lesbian couple" than me being trans.
Really, as long as you are providing for your child's needs, and they see you as someone who loves and cares for them, then the whole "being a mother" role becomes irrelevant, and mostly based within our own social constructs. Do what you can to be the best parent you can be, and you'll already be the best mother you can be.
H