sign baby is tired

how do you know if a baby is tired? Sometimes she starts crying, and I think it might be because she’s tired, but my sister-in-law keeps insisting that she just wants to play more. I’m worried that I might be missing the signs of tiredness and pushing her too much. What are the clear signs that a baby this age is tired? Here are some things I've noticed, but I’m not sure if they’re related to tiredness: She rubs her eyes and gets a bit fussy. Sometimes she yawns or her movements become slower. She seems less interested in her toys and more irritable. Are these signs of tiredness, or could it be something else? How do you balance playtime and rest? I want to make sure she’s getting the right amount of both.