Congratulations sa first successful pregnancy, that's so exciting! Most moms do it around 18-20 weeks (so around 4-5 months) when the ultrasound tech can clearly see the baby's parts, kaya karamihan namin nag-plan ng reveal around that time rather than waiting til 6 months, pero honestly, it really depends on when you want to celebrate and kung comfortable ka na mag-announce, so you can go anytime from 18 weeks onwards, no strict rules dito!