Everyone is different.
I breastfed both my kids, and for me, this is what I did:
I nursed until my kids self-weaned.
Even if the child is 1 years old, that does not mean you then have to stop, nursing/breastfeeding. The child can have both, the introduced milk and/or breastfeeding. There is no rule about it.
And, you also have to see IF, your child will take to milk or not.
Or take a cup or not. Or a bottle or not.
Per our Pediatrician, you nurse on-demand. And nurse BEFORE, any solids/feedings. Because, otherwise the baby will be too full, to nurse. Nursing was the first thing to offer baby.
And yes, you can mix breastmilk with cow's milk. But you do NOT have to to that. I never did that with either of my kids. They nursed. And then also had milk. Separately.
You just have to see what your baby takes to or not.
Each baby is different.
The reason for "milk" is that the "milk fats" in it is an essential nutrient for brain development. And milk is typically recommended through 2 years old. But your baby can still have, breastmilk. That is what I did with my kids. And you can serve it, separately. Or mix both together. Or not. Its up to you. And for me, I never added breastmilk to the "solids" my kids ate.
Everyone is different.
But with both my kids, they self-weaned. My son did so at about 1 years old. And my daughter at about 2.5 years old. The child, naturally just lessens the frequency of nursings on their own. Until one day they just don't want to and refuse breast.
If you want to wean your baby from breast, well you seem to be doing fine. And you baby is adjusting fine.
And you have a "deadline" that she completely weans by her birthday. So well, that is up to you.
There is no hard and fast rule, that it HAS to be done by a baby's 1st birthday. Not all Moms do that.