American classic ale bitter after taste.

So Its been a week and I wanted to check the SG. I did so and It was at the target. Instead of dumping I chose to drink my sample. It tasted fine up intil I swallowed it. Then I got an awful bitter after taste. I'm guessing it just needs more aging? The recipe even said to bottle to age 10 days to taste best. Just wondering if I messed something up? or if It just needs time. I'm guessing the latter.

Give it at least another week (preferably two) in the fermenter and then give it another shot...

Remember you are drinking warm, flat and young beer.... I tried to drink a hydro sample one time and that was enough for me. I still check for diacetyl if I am lagering, but see no need to actually drink the sample. Some people like to taste the changes, but I am not one of those people. Give the beer a week or so. You can taste it again then, but it still will be warm, flat, and kinda young. I find it better to wait till it's all carb'ed up before I pass judgement