Is it normal to have office romance?

Yes, esp when you are working together all the time, natural to develop feelings for one another, but still need to differentiate work and love life

When one spends most time at work, it is relatively easier to find the other half in the office; unless you are in a one-gender dominated environment. Whether it worked out, depends. So far, saw only one married pair - supervisor and subordinate. Once relationship confirmed, they were "separated" at the workplace.

Yes quite common nowadays. I have few friends that same company with their partner.

Yeah. Most working adults spend more than half the day with co-workers...