The belief that stimulation of the clit is necessary for orgasms comes primarily from an article from the radical feminist author Anne Koedt "The Myth of the Vaginal Orgasm". In which it is correctly stated that the clitoris has no other purpose than sexual enjoyment, but in which she also incorrectly states that all other forms of orgasm are merely extensions of the clitoral orgasm and are thus myths perpetuated by the men of the world in some chauvinistic conspiracy to keep from being deemed obsolete by women.
Many other experts have stated however, and I can attest to this, that orgasm can be achieved through stimulation of the clit, labia, vagina, anus, and many other places on the body, as well as through purely visual stimulation without any physical stimulation whatever.
If you're built in such a way that clitoral stimulation can be a challenge it is not surprising that you get more pleasure from vaginal stimulation, and if you've had a satisfying sex life so far I would'nt let that bother me too much.
And since you've always enjoyed vaginal stimulation more than clitoral, I've included a link to a chat of areas in the vagina that are currently known to be extra sensitive to stimulation.