I would guess at too much if they are going black. Too little will show as brown as the tips dry out. They do not need much water and need plenty of light.
I'm no gardener but about 3 years ago my daughter brought two tiny aloe vera plants home, they were both around two inches tall.
She put them on the window sill in the bathroom which is shaded ... they never get watered... but have grown like nothing on earth....they have since been re-potted twice and now need doing again.
So it appears the warm moist air/steam that they receive in the bathroom suits them, and no extra water at all.
When a plant has fleshy leaves , they retain the water, so this should be an indication of whether to give a plant lots of water or not. The Jade (money) plant is the same. Bit like a cactus.
I would definitely say you have overwatered it and from past experience you might lose that plant. As someone else said, they need hardly any water & can go a long time without a drink but do love and need light. I have a huge plant and the sticky sap from the leaves is fantastic for spots, scalds etc but if you open up a leaf from your plant I think you will find it will be very watery; a classic sign of overwatering.