Most psychologists argues on the concept of maturity. But anyways, yes. it is called you have crushed on someone when you got an slight feeling on someone; which means the love hormones in our body have been released in our brain for that person. If these chemical reaction stays for a little while, we call it crushing; if long, it is what we consider it love. SO, those people who are considered matured may have crushed on someone. But if he falls, it means he loved. And yes, matured people can love. He is still an healthy human being.