People speak in words rather than numerals. That’s why you wouldn’t type, “Dude, I called you 2 times!” into your fictional dialogue. Same thing goes for typing a measurement into dialogue. The height measurement in your example should be spelled out in this manner: “five-feet-four.” For a character with a more casual speaking style, “five-foot-four” or “five-four” will do the job nicely. Since internal thoughts are essentially unspoken dialogue, they get the spell-out treatment, too.