What do flutters or "quickening" feel like?

15 weeks and 4 days I know it might be early but I'm curious. These past 2 days I've been feeling little semi hard pressure on some points of my stomach they don't hit the same spot all the time I lay on my left side a lot and I feel it there mostly and my right side I feel the same thing as well especially at night. Is it my baby moving or is it just in my head?