Re: Why now?
Perhaps you need some "me time" before thinking of putting energy into another relationship. Time to heal from your past relationship, time to reflect and understand why things went wrong, and to help define what you're looking for in a partner and life in general. Combine this with your responsibilities of learning a new job, and that's a lot on your mind right there.
There's no rush to forge ahead with this potential person. Give yourself some time to acclimate to your new work environment and get to know your co-workers. This will give you the opportunity to observe more about this person before coming forward with your feelings.
Remember it will be difficult to maintain privacy in such a close environment. Extra caution is needed as you know how people can gossip. And often most office policies frown on co-worker romances, be sure you know where you stand before coming forward as you wouldn't want to put your job in jeopardy. Once the "news" is out, everyone knows.
Being you're a new employee puts an extra spin on your situation. My best advice would be to prioritize your concentration on your new position. If this has been lagging, remember your boss is observing your performance.
Incidentally, I dated a former employee after I took over his position. This began a year after he left the company. We've been married for six years.
Best wishes, Flower