18.
BUT....I had a slip today. I unintentionally saw an image that was inappropriate. Don't ask me how, it just happened. HOWEVER, the amazing thing is that my eyes instantly moved elsewhere, without any conscious effort! Might sound strange or like I'm making it up, but that's what happened. I didn't see it for more than probably a tenth of a second. In fact, I didn't even recognize it. So I consciously said "wait, was that really what I thought it was", and looked again to make sure I wasn't fooling myself (because that image was NOT supposed to be there), and sure enough it was inappropriate, so I looked away quickly (both looks were maybe half a second altogether). Maybe I'm not being very clear because it's 1 AM and I'm very tired, but the point of all this is that my eyes are smarter than I am. I have apparently internalized the desire to stay away from all that to such an extent that my eyes automatically looked away as soon as my brain registered what it saw, even though I hadn't yet. I should add that this is sadly not yet the case with clothed women, such as what I see every time I go outside, but that's a higher level.
At the risk of sounding self serving, I was pretty pleased with myself when I realized what actually happened!
But I can't get complacent.