How and when to tell my kids mommy is pregnant!?!

Rose

Hello ladies! I am 38 and pregnant with my 3rd. Last year I had a chemical pregnancy so I'm really hoping this one sticks. I am 6 weeks pregnant as of today and my hcg levels are 1600 + so my Dr says it looks promising.

I have a 15 yr old and an 8 year old. They both have really wanted another sibling always talking about "when the next baby comes, etc". My 8 yr old has a list of girl and boy names ready since last year lol. So ladies any ideas of ways to break the news to them?