Would I know if I have been concussed? 15M, 5’8

Around 30 minutes ago, I got out of the pool and walked to the changing rooms. The floors were hard brick, and I slipped and fell and hit my waist, then I hit my head with a short interval of around 0.1-0.3 seconds. I don’t know if my waist absorbed most of the energy, but when my head hit the floor it hurt and my eyes had this weird white flash thing? (It has happened before, and I was fine) and no ringing. There is no ringing now, no headaches, and I can talk now how I talked before. My family seemed pretty nervous and were like “You’re okay from that?!”

It was quite a fall, but apparently concussions can kick in a few hours after. Am I built different or am I not gonna be able to talk for a while? Any response is appreciated