Of course gay people exist, but they are a tinier proportion of the population than the gay-populated media would have us believe.
The fact of the matter is that most people are heterosexual which is a biological truth in order to propagate the species. If everyone was gay, the human species would die out. However, maybe Nature has that one sussed. If war can't cull the population any more, then perhaps Nature has devised a method of preventing too many births.
I don't know whether older people are more likely to be reserved about their sexuality. We certainly grew up during a period when homosexuality was illegal and a crime, but also at a time when society was rethinking its whole ethos, including the rights of gays.
I know a few lesbians, and I don't know if this pertains to all lesbians, but those I know come from good families, but had spent themselves, heterosexually, by the time they were 15, and their sexual excitement was lost. For them, adopting a lesbian lifestyle had two effects. It re-ignited their sexual adventurousness, with the added effect that it shocked their middle-class parents.