Help teenage guys and girls?

well i metb this guy he 15 soon and im almost 13 hes my mums best mates brother and well we met each other a few days ago but he started play fightin and tickilin me and then he started grabin my **** and stuff i like him and hes really sweet but im scared cause hes older than me that hes guna try (well erm ya no) but i feel like a slut and stuff can u help is it bad hes grabbin my **** (he likes me aswell not just grabbin my ****)(i think) but the thig is ive never even kissed a boy nevermind let one grab my ****