I'm 14 weeks and I can feel mine. My dr. showed me how to find it at 11 weeks. I was retroverted, but it's righted itself now. Sometimes it feels different shapes--more bulging at the top or at the bottom, or towards one side.
Before, when I pressed on my belly or abdomen with my muscles relaxed, I could push it pretty far inwards and it felt soft all the way through. Now, it feels more firm beginning about a finger or two below my belly button. I can sort of trace its roundish shape. Down low, between my hip bones, it tends to be very noticeable.
Like someone already said, it's just firm--not hard. Sort of like a water balloon.