Hi ,, I’m mother of 3 boys 6,5,19months

This baby is number 4 and it’s surprising as because last month I removed my copper iud I thought it will take couple months or more ,, I’m so happy but the problem that i just praying it will be twins ,, I know it’s sound crazy but I don’t know I want twin girl and I can’t stop my self from dreaming all the time and watching videos for twins ,, For sure it’s only one baby ,, is it normal this feeling?? Any one with me 😁 for twins mum how you know you are pregnant with twins and when ?? Thank you so much

Baby 2/4/2020