How do you process things quickly

I know this might seem like a silly question... but hear me out. I'm 14 and 5'5 so already a huge disatvantage. But people at my high school literally kick rockets. Top corner, bottom corner, everywhere. I saw another post that basically said "If they kick at the top third, form a W with your hands. In the middle, bring them closer. And if its a low shot, make a cup". But how do I even have time to react when they shoot a ball from 7 yards out at like 100km/h at a net that's 20ft in length. Also crosses and corners are a nightmare for me because I can never come out and catch the ball. It's so slippery and always deflects. I read somewhere that you have to not tense your hands with hard shots so it loses momentum, but I can't react quickly enough. I know this is like a rant but we lose by 5 or 7 goals everytime and I barely have any saves, its starting to get frustrating.