Why It's Pointless:
We bet you saw this coming, but this might be the dumbest, least-necessary sacrifice in the entire Marvel universe, or any universe. Quicksilver is literally the fastest man alive. We see multiple times how he perceives the passage of time and how boringly slow everything is compared to him. Every moment for us is like days of him watching the world buffer.
Let's start with the obvious. Instead of jumping in front of bullets, Quicksilver could have shoved Hawkeye and the boy out of the way. Or picked up something bulletproof and put it in the way. And while on the subject of bulletproof, aircraft guns shoot giant bullets intended to punch holes in other (metal) planes -- they barely slow down when passing through the mostly liquid meat of a fragile human body. If your plan to protect someone from a jet is "human shield," you most likely died years ago from assuming the suffocation warnings on a plastic bag were sarcastic. All Quicksilver would have done by standing in the way was make sure the two were killed by well-lubricated bullets.
To make matters worse, he catches a bullet earlier in this movie. He's fast enough to pluck speeding bullets out of the air, which means that standing still and letting them tear into him would be like one of us letting a sleepy tortoise slowly crawl over and chew through our neck. There are an infinite number of options to avoid not dying here if you have super speed.