Convert a bike that is a mongrel or missing drivetrain parts. Don't convert a complete, original, perfectly functional, and nice-looking bike like that.
What functional advantage do you expect to get from a single-speed conversion? You will struggle up any real hill. You will fall behind on fast flat rides. The chain line will be straight, but the chain line is already pretty straight in the current gear combination that probably approximates what you'd choose for a single speeder (like 39 X 16, etc). You will not have to maintain the derailleurs and shifters, which will save you maybe 15 minutes a year. The bike will be a few pounds lighter, that is about it.
I think most single speed conversions are just about style. People think it is cool to ride a faux track bike on the road. I think the stripped down speed machines look pretty cool too, but on my commute I blow by single-speed riders all the time, and I think it must not be so cool to be getting routinely blown away by some 50 y/o guy on a 30 y/o bike.
Anyway, you can test it out. Stick the bike in one gear and ride that way for a few weeks or months, no shifting ever, no cheating no matter how much your knees scream, get off and walk instead of shifting. Maybe even use the limit screws and lock the drivetrain in that gear. See if you like it.