Mommy, hi! Can you tell me roughly what age kids start falling asleep …

Mommy, hi! Can you tell me roughly what age kids start falling asleep independently without rocking? We have problems with bedtime. We can't turn off the lights, we can't rock her on the pillow for 15-20-30 minutes and she won't fall asleep. She might sleep in the car or stroller, but only rarely, and only if the battery is completely dead. In public places, she doesn't fall asleep at all. Not even in the park, cafe, or when visiting someone, even if she really wants to. Roughly how long will this last? The second one is coming soon, and I don't know how I'll handle two of them. I would like her