18 weeks don’t feel movement

It largely depends on where your placenta is. I’m 21 weeks and just now feeling kicks

If it’s your first baby you might not feel kicks until 22 weeks.

I’m 19 weeks and i still haven’t felt anything which i was worried about at first too but in speaking to coworkers it seems more common than i thought

Maybe you have an anterior placenta, but you can confirm with your ultrasound technician they can explain and locate it better in your next appointment

I didn't feel anything I was confident was baby movement until the day of my 20 week scan which was at 20w1d.
(First baby)
Also my baby measured in the 97th percentile, so you'd think if he/she is that big I would have felt something sooner unless it's normal not to yet.

I’m 18 weeks and haven’t felt anything

Yes that can be completely normal.