This is a very easy question but I don’t completely understand the reasoning, can someone please clarify?

Question A $1000, 5%, 20-yr annual pay bond has a yield of 6.5%. If the yield remains unchanged, how much will the bond value increase over the next three years?

Answer: $13.62

When i calculate using TVM in my calculator i get $834.72 over 20 years. When I change N to 17, I get 848.34. I dont understand why the bond would increase as it seems to me that I got the higher number when at 17 years and then it decreased leading up to year 20.