The flower is a metaphor , it has double meaning one it is about the feminime reproductive organ, aka vagina, but it has rather a religious meaning , the women soul isn't the same after she made sex for the first time , the flower is still about the women innocence and soul pureness ,so because she gave birth she ruined the physical aspect of the flower methaphor, but the spiritual part stood intact. The show wanted to make us understand that for a Christian at least , as Jane , to make sex is a really big responsibility , and to make it you have to choose the right person , and at the right time. She didn't make sex before not only because of her Abuela and her flower methaphor but also because she wasn't complete ready to do it herself . For Jane sex, at least at beggining was way more than it is to us today, it was the ultimate prove of love and trust not only a phisiological action, it was also a plot divice, an indicator to make us understand who she really loves, who she really trust . Unfortunately in last season it lost that meanings , and we get to see the carnal part of sex in Jane's life too , now sex isn't anymore about love or trust, but also about desire and phisical need.