prenatal vitamin

Jenny
I recently stopped taking birth control and my husband and I aren't really trying to get pregnant, but would be happy if we did. 
I was at the store getting other vitamins and thought I should get prenatal vitamins, but my husband said I wasn't pregnant so I shouldn't get them.
When should I start taking prenatal vitamins? Should I wait till I get pregnant? 
Also, how long to you take them, all during your pregnancy
#iamNew@this