Most women irrespective of age can have the occasional smell down below and this is generally caused by an hormone imbalance, even doctors are puzzled why this just comes and goes for no reason, but it is called Bacterial Vaginosis, other wise known as BV and it can cause a nasty embarrasing smell. However it is treatable and it is not caused from too much or too little sexual encounters.
Also Thrush is the most common, however. that does not cause the bad odour of BV, an over the counter remedy for both of the above normally fixes up the odour and you will be squeeky clean once again. Although having said this it is always best to use a condom at all times even with blow as thrush can be in the mouth too and can be passed on from mouth to penis. have a good smelling day. lol

sorry also forgot to ad by wearing very tight jeans etc can cause vaggy probs. also nylon panties (which i am allergic to myself)
also a mild soap...nothing too scented because that can also cause problems with attracting thrush etc. Go girls and make lotsa money

I think cleaning regularly in warm water and clean undies helps prevent smell.
Also regular paps help control germs.

Taking probiotics daily can also help to a large extent.