Baby's quickening is slow and less?

Aroosa

Hi, I'm 25 weeks pregnant with my first baby. I started to feel my baby's movement at 20th week but from the beginning it was quite slow and less often, I thought it's gonna increase with weeks but at 25th week, still it's mild and only (feels like vein pumping) in womb. I know, the kicks will be felt at maybe 28th week or so as I heard but why does not my baby moves fast or something like that? Is it normal?