Is the origin 1500 medium right for me

Hi, I'm looking at the Origin 1500 Medium firmness. I'm quite light for my height (6'2") but only weighing 11 stone. Is this the right mattress for me? I'm currently getting a bit of a lower back ache from my 3 year old Silentnight miracoil 7 Jupiter. I'm not sure if I should go softer for my weight or medium for my back.