My co-worker got married on 6/30/12 and we had an office shower for her on 6/14/12. Her and I are pretty close because we are around the same age and we are/were planning our weddings at the same time, so I decided to purchase a gift off of her registry. I only spent about $25 and I gave her the gift in private before the office shower. She was pretty taken and back that I got her a gift since I have only worked at our office for about 6 months and we haven't known each other that long. However, I still haven't received a thank you note or even a thank you email for this gift.
So my question is how long to people usually wait to give out their thank you notes? Am I wrong in expecting some sort a written thank you from her?