Any position takes practice, and not all positions are good for you or the baby. The way that babies are built makes them spread weight evenly when facing in. Their limbs bend and cling. When facing outward, their limbs dangle which pulls on the adult carrying. It's better for your back to carry facing in.
Also, it may seem as though she only likes to be carried facing in, but when she is in-arms, you can easily shift her around and meet her needs. When she is in a carrier, it is easier to get caught up doing something and not meet her need to prevent over-stimulation.
It is also much harder to carry a baby in the correct ergonomic position if they are facing out. Facing out positions lend themselves to dangling a baby by the crotch with their legs straight down. Extra measures must be taken to ensure that the baby's hips are rotated, with knees up above bum level . . . especially if they are facing out.
My son didn't take to back carries immediately. We had to practice. Once he figured out what I was doing, he stopped fighting, arching his back, and screaming. Now I can throw him on my back and have him wrapped or in a buckle carrier in 30 seconds.
To do a back carry, practice with a sack of rice or a teddy bear first so that your body is at least a little familiar with the motions. Then take your daughter and kneel on the bed to practice. It will take a few tries (and even longer if she fights like my son fought) but if you stay calm and work through it, you'll have a valuable new skill to be proud of.
If you would like more personalized assistance, I teach BabyWearing and I can do some consultations with you through PM or email. I'm here to help, if you want.