I had the same question. Even the dates you mention are the same as mine. Transmitted 1/29 , but accepted 1/23.
I called the IRS this morning and asked about it. They said that they may very well have accepted the return on 1/23, however actual processing of the return will not begin until 1/29.
Using this timeline, 21 days will be 2/19. If I dont have any updates by that time, I will call them again.
