So big, yet, so little

My 7 year old is trying so hard to grow up and keep up with his 4 older brothers. He still has a pillow that he cuddles with yet, he had learned to ride a bike at 4, learned to ski down hill at 5 (hitting the difficult hills), and kicked a soccer ball before he could walk. So, today he tells me to watch him hit ramps and jumps and quarter pipes with his bike. I go outside, admire his new achievements that are as accomplished as a 10 year old. Then, he comes back in the house, cuddles his pillow, and tells me how he wants to go to a skate park and hit jumps. All the while, he is grabbing his private area, wiggling, holding pillow, and wearing a t-shirt that says, "I'm going to tell Daddy." In the other room, the big guy is listening to rap music, chatting on Facebook and working on his literature book for his AP English class. Does that seem odd? I have the youngest and oldest both trying to grow up before their age allows. Moments later, the youngest crawls up onto the big guy's lap and they snuggle for a while, chatting about their biking adventures. I really do love having the huge age gap between my children. But, I hope somebody reminds me of that when the youngest is in college and the oldest getting married and I'm flat broke. It won't feel so wonderful then, I suppose.