Off bitter flavor

I recently made my first american barleywine about a week and a half ago. I did a gravity check the other day to see how things was going, and tasted it. It had a OG of 1.114 and IBU of 99. Now the SG is 1.029. At first it tasted good, a little sweet with a good bitterness, but the bitterness lingered to leave a bad bitter after bite. Is this normal for a green barleywine? Will this go away when I age it?

Yes, green beer can be quite bitter. Also if your water has a high level of carbonates, this can lead to a harsh bitterness - which will pass with time. Generally barelywines are aged for quite some time so being a bit on the bitter side when young is a good thing, IMHO. If you under hop, by the time the beer is properly aged, it won't be bitter enough and will likely taste too sweet.