I think it's fairly normal to a certain degree, but not so normal if it's so often that it gets in the way of & interferes with you every day life. Jealousy comes from a combo of underlying emotions commonly including - Anger, inadequacy, resentment, helplessness, anxiety, insecurity, and fear. These emotions are brought about by negative thoughts (often we aren't even aware of having them)
Commonly, we have these thoughts & feelings due to the fear or anxiety of an anticipated loss of something we value or someone we value/that's important to us.
Examples off of the top of my head: 1. A girl is feeling jealous that her boyfriend is spending the day with his friend. Her jealousy is likely stemming from losing time the couple usually spends together. She probably has thoughts like, "Why did my boyfriend choose to spend his free time with his friend instead of with me?" (Insecurity & fear) "I'm not good enough or fun enough to be around" (Inadequacy & fear) "I always choose to spend my days with him & never pick my friends. It's not fair that he gets to choose to see his friends when I always choose him first & spend all of my time with only him" (Anger/Resentment)
2. An employee becomes jealous of his co-worker who just earned a promotion. The employee probably has thoughts such as "Why did he get a promoted instead of me?" "Our boss thinks he's a better worker than I am" "It's not fair that he got a promotion when he's in high school looking to make some extra cash. He didn't need the promotion as much I as me.. I have a wife & kids to feed, bills to pay, etc...." His jealousy is likely stemming from his personal feelings of insecurity, inadequacy, and fear.
I think many women are that way.Its in they're nature.