What level should I start PK'ing on Runescape?

Im combat level 60 and am going to become a member today. Im level 50 attack, 50 strength, 50 defence, 48 constitution and 28 prayer. I've saved up 450k to buy full granite armour and a granite maul once I become a member. But I'm not sure if I shold start PK'ing? If I should start, what items should I take?