"personal guess" is correct and usable in written English.
You can use it when you are expressing an opinion or estimation based on your own personal knowledge or experience. For example: "Based on my personal guess, I estimate that the population of this city is somewhere around 200,000."
"That would be my personal guess," he said, adding that the findings had to be checked in laboratories.
On why most of these images did not appear before now: My personal guess is that after the convention concluded with the nomination of Kennedy, nobody was interested anymore.
"My personal guess, however, is that they might try but they will fail, and we will not see a successful North Korea lunar orbiter for at least two decades, if ever".
My personal guess is that in the near future, whatever optimism people are now feeling about Japan's economy will evaporate, and the nation's malaise will be deeper than ever -- thanks in large part to Friday's action.
My personal guess is that by then the 99 cent figure will be lower, both for the new Napster and for other legitimate services.
My personal guess: a highly versatile browser with a ton of APIs ready to be taken advantage of, launching with partnerships and a few new services so that it can be a tolerable replacement for a netbook or laptop.
But is it worth it, at the cost of introducing the happy couple into a maelstrom of second-guessing, personal criticism and unpleasant speculation about their motives?
In efforts to remain calm, he recalls counting how many puns about fire he could think of to lighten the gravity of the situation: "I got that skylight I always wanted!", "I got fired from my job!", or his personal favorite, "I guess I'm having a fire sale!" True to his personality, Medanksy continues to find the silver lining in the unfortunate irony of his situation.
Personal experience, I guess, because if I did I'd be a mess.
If I use the phone of the Council for personal use, well, guess what?
And, after three long years of sharing life, laughs, and a lot of personal slights, I guess you're finally moving on to bigger and better things than me constantly using your razor (and not on my face).
