This outfit is absolutely adorable.  My son is 4 months and just under 17 lbs.  I ordered the 6 month size and it was quite a bit big as expected, but he still looked adorable and extremely comfortable in it!  The fabric is super soft and the detail is super cute.  The only reason I'm giving this 4 stars is because the hat is super tiny.  I couldn't even come close to getting it on his noggin.  I wasn't super set on him wearing the hat so it wasn't a big deal breaker, I was just shocked to see the outfit being so big and hat being so tiny!