Like others have said,please take it slow. You can always do more but you can`t take it back if it gets to be too much. If you`re going to be with someone let them know what you will be up to,just in case.
I wish I would have followed my own advice a few years back.8)
I had tried ket more than a few times in my early 20`s but never had a gram to myself. It was always some friend giving me a bump here and there during a party. That sort of thing.
One day I got a gram(at this point I was in my mid 20`s). I had been doing small bumps and small lines over the week but by Friday I wanted to feel it a bit stronger.
So while my GF was smoking weed with company in the living room I went off to the bedroom to play some acoustic bass and do some K. I used to be a heroin user so I still had a rig. I decided to lay out a line,then I dumped it into a spoon and shot it up into my thigh (IM injecting it),figuring that it would slowly take hold and be enjoyable.

Well as it took hold I set my bass down, then slumped over on the bed. I went right into my first K hole. After all the years I had dabbled with it while partying,usually on MDMA or LSD this was my first time taking it sober. The high was so intense that I actually forgot I took a drug! I started to think I had gone clinically insane while I was having(in retrospect really cool) vivid full on fantasies. Not hallucinations but a total fantasy about running around my drive way with my girlfriend`s daughter in a head lock and laughing.
I guess I had been too quite for about 15 minutes so my girlfriend popped her head in the room to check on me. I had a technicolor caterpillar crawling around my vision blocking out everything but a tiny window of reality with my girlfriend`s head in it.
When I saw her I started to cry with relief that I "finally" saw some someone I knew amid all the zaniness.
Not too long after she sat down with me it started to wear off to a much more enjoyable level. Even though it was terrifying at the time looking back on it,it was a really great display of what ketamine has to offer those willing.
Sorry to ramble(6-apb will do that),long story short: I recommend that you try it out,just start small and work your way up!