Letter transcription:
Dear Bonnie (and David)
As of now our plans are to visit you the last weekend in Oct. We will probably fly to Boston Thurs. the 28th and come home on Sun. I hope that won’t conflict with your schedule. Since it is this far away, let us know in case we would need to change our plans. Sorry I am so late with your greeting but Sept. 1 seemed to slip upon me. I wonder why.
Love Mother
©2017 copyright owned and transcribed by Deborah Sweeney
Post originally found: https://genealogylady.net/2017/03/15/belated-birthday/
Genealogy Lady 
Duh. I totally missed that.
” but Sept. 1 seemed to slip upon me.” Hmmmm….I really don’t know what she meant by that. Clearly this was written sometime during the last week of September.
Sept. 1 was Bonnie’s birthday. This was a card for Bonnie.