It doesn't have to be be the next in-order milestone!
My son is 3.5m and I look forward to starting him on solids! I can't wait because it will be super fun to see his reaction to certain foods and to get all those fun spoons and bowls:)
The milestone I've enjoyed most so far is the social smile:)
Just for fun here's a pic:
Please include pics of your milestone if you wish!