For those of you with toddlers/older kids (ones who would understand) when did you tell them you were pregnant?

So, this is super premature as my appointment for my implant removal isn't until next week so we're not even TTC yet 🙈 BUT, for those of you with older kids (ones who would understand and weren't babies themselves) when did you tell them you were pregnant? How old were they when found out? How did they react?

Obviously you would want them to let the cat out of the bag before you make it public, but on the other hand, how could you possibly contain yourself and not get excited that your LO's will be a sibling?!