I am 18 years old...can I have diabetes..should I get checked?

Listen to Tabea! Unless you are thirsty all the time and can't stop going to the bathroom you are definitely not type 1 diabetic and more than likely not type 2. The lethargy and hair turning gray could be from other things. Itchy toes could be a fungus not something a diabetic would show early on. You are predisposed to diabetes so you have to watch your weight and exercise 3-4 times a week otherwise you have a good chance of getting type 2 diabetes.