help today and how long since day X?

I am trying to create a training database with Date entered training/today's date and how long they have been in training.

The first day is something that is a set day, but I would like it to auto update the next two fields so the people that have to fill the the sheet out only have to plug it in once. The people are lazy and I dont trust them to update this as often as I need and dont have time to double check it before the meeting.

Is this posible or will I have to beat my apes in to submission?