I like being single too.
I don't have enough space in my life for a girlfriend.
Firstly though, this girl seems a bit full on doesn't she? Turning up at your work, bombarding you with SMS before she even met you? Imagine how high maintenance she'd be if you had a relationship!
If it's at all possible, just do what I'm doing with my virgin girl (I don't like to brand her as such, but it means you know who I'm talking about). Just go on a few dates, have some fun.
You don't have to have sex with her. And you don't need to make it serious or anything. Just have some fun. If it gets too intense, you can always stop it - it's a lot easier than committing to her fully for now.
If the dates and the fun are really great, and you feel like you could commit yourself totally to this girl, THEN take the step and make it more "official". Until then, don't take it all so seriously