This was my first indoor woodworking project, where it mattered if the corners were 90 degrees and the colour matched and the wood was not warped.
Even when the lumber yard gave me the wrong width of board, did all the cuts and I didn't notice until I was home, laying out my pieces and measuring everything, I will still able to complete it.
I went with the 10" (9 3/4") wide top instead of the 12" (11 3/4") rather than go back to the lumber yard and have it recut. I was anxious to make my project and it was a hassle to drive that distance. it didn't have the 1 1/2" overhang that the larger width would have had but it fit in my tiny space better.
The next time I visited that lumber yard for more wood, I got my money back and I learned a valuable lesson - just because the lumber yard staff are picking up the wood for you, you need to read and check. I didn't go closer to see it because of Covid-19 restrictions but next time I will ask to measure it and check it before I bring it home. I've learned to carry my tape measure with me, just in case!