Where do I start?

So, I just started MFP a couple days ago and so obviously haven't lost any weight yet while tracking on here. I have however in the last 6 years (i know it's a long time) lost 81 pounds through different attempts of healthier eating/exercising. I haven't gained any back and have maintained my weight the last 6 months or so, so I am at the lowest weight i've ever REMEMBERED being. Should I count that weight loss on here? I mean it is a big chunk of weight and sometimes I forget i've lost that much and how much of a big deal that is and how proud I should be of myself! OR should I just keep it as a little addition to a conversation "Oh i've lost #ofpounds since Jan 2011, but altogether at my highest weight i've lost #ofpounds" .. if that makes sense.

I don't want to forget about the weight i've lost because I was so heavy that I promised myself i'd never go back, but I am very serious about weight loss now and I KNOW i'll have some before/after pics .. but should I try and find some at my highest weight or take a new before picture now.

Sorry if this was confusing!