Well it really is hard to bandy around distance and ride times without a context. Was it heavy stop go traffic, loads of traffic lights? Does your cyclecomputer not register movement after a certain time? Were you using slicks or extra chunky knobbies? Was your tyre pressure low? Is your gearing adequate? Is it super hilly where you are? Head winds as you mentioned? Etc, etc, you get the picture.
As others have said, don't worry about it, just get out and enjoy yourself. Chances are you are faster and fitter now then when you started! (and that's a really good measure) . If you are concerned, just start timing yourself to see if you are getting faster (just don't be a slave to the time at the expense of your own safety).