Well, my guess is less observant than you.
Meghan wore three stack rings from Ecksand at the Landover event yesterday. What's interesting is the stones that's been identified: Peridot (Meghan's birthday stone), sapphire (Harry's), and then one in diamond (April). So I went back and counted 40 weeks from beginning of April and end of April. Putting her between 12-16 weeks when they announced. Now, given we know she has had her 12 week scan already before Eugenie's wedding, it's unlikely she's 12 weeks. I think she'll cross the threshold of 4 months some point on this tour. She might not be exactly 4 months yet, but very close. Missy Higgins basically confirmed that when talking about meeting Meghan.