Actually I think that you are right at the age when perimenopause starts really kicking into gear. Weird, irregular periods can last for years and years. These hormonal changes aren't like flipping switch. It's usually not an overnight process...it takes time.
Since this is a new symptom for you, I think it's good that you are getting it checked out. In fact, spotting in between periods is usually a good thing to get checked out.