I would follow your heart and if possible re-visit the litter for a personality match with you.
When I was looking for Lucy I did not have the knowledge I have now about size so I was looking for a very small Yorkie. Once I was at Andrew's I played with each of them for a LONG time and ended up with Lucy who was the largest of the litter and she's ended up to be 3.5 lbs. Lucy totally chose me! She came to me and cuddled up so close to me and looked at me with her beautiful eyes and I knew.
I can certainly see your concern with having one so small around others.
Best of luck

So, you will have a Christmas baby-how exciting!