I think that teenagers have a wonderful capacity for love, and the same capacity for every other emotion under the sun. What many teenagers may lack is the wisdom of someone they trust who is a little older and hopefully a little wiser, to confide in and to guide them during those first tentative steps.
A teenager's emotions are all over the place as they hurry to try and keep up with their hormones. Add to this their desire for independence and the need to develop their very own emerging and unique personalities and still find acceptance, and you have the makings for some very explosive emotions.
The passage from teenager to adult is often fraught with high energy and impatience. When emotions are added to this mix it can be difficult but absolutely not impossible to differentiate between love and lust. However, impatience may influence some decisions they make.
I certainly believe that teenagers can know love. The telling point I think is how mature they are when they find it, and in knowing what a wonderful gift it is to have someone love you.