LO crying when feeding purees

FTM - my LO is 5 months and at his 4 month check up our doctor told us to start our son on purees. We've been trying to do so for the past couple weeks but he keeps crying.

It seems like he enjoys it but then after a couple spoon fulls he gets very irate.

Not too sure what this means but I'm guessing he's not ready for foods yet.

It's odd because he'll excited when I prepare the food and get excited when I'm about to feed him, then as mentioned after a couple spoons he freaks out.