What is your definition of love?

A lot of people will say " oh your too young to know what love is" but is it possible to be in love when your 18. I highly believe its possible. ive been with my boyfriend 7 months now and i have no doubt that i love him. He is the only boyfriend ive had that i can truly say i love. I just want to hear you opinion on what you thi nk love is. what you feel, signs to show you are in love. basically your defintion of the word love itself.