Piano/Keyboard, help IMPORTANT question.?

Hi, I want to learn how to play the piano and when I told my mom she bought me a keyboard, but she's really tight on money so she bought a keyboard with 61 keys; Casio CTK-720, I don't want to tell her but i wanted the full 88 keys. Is it possible to play piano with this type of keyboard? Also do I have to get keyboard lessons, because I really want piano. Please help!