Should I be concerned?

My Lo is 10wks. And we recently had her 2 month check up and Doctor said she has good strength but I feel a little concerned still because she BARELY lifts her head during tummy time. And only will lay on her tummy without crying for a couple minutes. She does hold her head up while I hold her on my shoulders but barely lifts it during tummy time. I see all these babies on here her age or even younger with their head held high. Anyone else's baby not lifting head during tummy time?