new rider

im a new and i never rode motorcycle before and 30% of ppl tell me to start with a 250 and the rest with a 600....my cuzin has 2 suzukis 600 1 for show and 1 for riding and he spoke to me and said he will give 1 of them and he is going to start on giving me lessons on monday on the 600 but he said if i want o start with the 250 and he will keep it in his garage so i dont get tempted and then he will give it to me after a year..what should i do?