Do you have any experience of walking at altitude?
Altitude can affect anyone regardless of age, sex or general fitness. At 2200m, the altitude of Paro you are unlikely to experience problems - may be a bit of breathlessness. The degree of severity can vary and some people are affected at lower altitudes than others. Altitude isn’t usually a problem until 3000+m, but some people can start to be affected around 2500m. How active you are can also affect this as the body needs time to adjust to the lower oxygen levels.
One thing in your favour is that you will be sleeping at lower altitudes. (Advice is to go high during the day but sleep low.)
Bhutantravellers advice is sensible. Take it slowly and steadily and DON'T push yourself. Don't be afraid to tell your guide to slow down! If you find you are having problems breathing or are getting a severe headache or beginning to feel nauseous (all signs of AMS) think about giving up and going back down again. This will help symptoms ease. This isn't a sign of weakness but common sense. There is no point in ruining the rest of your holiday. Not everyone who sets off on the climb makes it.
There is some advice on altitude here:
http://www.altitude.org/altitude_sickness.php
http://www.traveldoctor.co.uk/altitude.htm