Baby fighting sleep

She started doing this almost a month ago.. she’s three months. When I try to rock her to sleep she starts scratching her face, swinging her arms and crying until I can calm her she tries to fall asleep then she opens her eyes again and does it all over again until she officially falls asleep. I’m positive that’s what it is. She rubs her eyes and she always fall asleep I’m not forcing it on her to sleep she just fights it when she’s tired and idk why.. she’s been giving me a hard time