POD that in my dh's family, a bridal shower can actually be about family circle or parent's friends as much as about Bride's own friends.
[sidetrack] Also, depending on the prevailing culture and average age of marriage, the association of marriage to "welcome to adulthood" may be more about custom and chronology than about any sort of negative attitude to singleness. I got married at what was considered an "average" age where I was living at the time, but that was 10-15 years past the average in my hometown. My well-intentioned relatives back home really kind of didn't know how to treat me, as I was obviously a mature and self-sufficient woman. They were accustomed to Brides who might not be old enough to drink, or vote, or just barely.
Even now, the parents of some of my kids' playmates are so much younger than me, they feel obliged to call me Mrs. Lastname, since I am the same age as their mom!