How could I have waited so long, Miss Pym?

You, like me, have probably heard for years about the wonders of Barbara Pym, the late British novelist. I hope, unlike me, that you dashed out to read her. For some reason, I hung back. She was often called ''A 20th-century Jane Austen, '' a sobriquet I found more off-putting than appealing, as precise and amusing as I think Jane Austen is. Did we really need another one?

At any rate, after having my nose pointed toward Pym by more friendly readers than can be counted, this fall I relented and introduced myself to her. It was love at first chapter.

Pym's world is a small English one, peopled by mild eccentrics and endearing village characters. Vicars and curates, spinsters and widows, gossips and small-time exploiters, kindly men and thoughtful women - these are the figures in Pym's tales, and virtually without fail, each one is brought to irresistible life.

You see the surface similarities to Jane Austen. But the quality that separates Pym from Austen, for me, is the same quality that separates her from most other authors writing now or earlier - her voice. And a singularly distinctive voice it is, one that is outwardly fragile, yet inwardly piercing. Pym has an insightful manner of putting words together.

It can be tiresome to say that a writer is ceaselessly observant, because this is a trait unjustifiably attributed to rows of novelists. It is justifiable in Pym's case. Although she forgives her characters' idiosyncrasies, she doesn't fail to tweak their follies fondly. Pym's humane view of life is warmly attractive, and on top of that, her humor is inescapable. Most readers chuckle their way through her books.

My own favorite Pym is ''Excellent Women,'' the second book she published. Other Pym readers cite ''No Fond Return of Love,'' ''A Glass of Blessings,'' or ''Quartet in Autumn'' as favorites. (The last named is perhaps her most melancholy work.) There are 10 Pym novels from which to choose. All are available in hard cover from E. P. Dutton, and all are available in paperback in Harper & Row's Perennial Library line.

Anyone who has already read Pym's novels may want to learn more about her. The opportunity to do so is found in ''A Very Private Eye: An Autobiography in Diaries and Letters,'' edited by Pym's sister, Hilary Pym, and Hazel Holt.

Barbara Pym had a difficult life as a writer, for she watched her literary reputation dry up in her own lifetime. It was only just before her death and afterward that her achievements were loudly acknowledged.

''A Very Private Eye'' was published by Dutton this summer. No paperback yet.

Now then. We have gifts to give. Everybody knows that I like Pym books, but what books are right for Chuck and Sally and Sylvia and George? Of them, only George has yet to read Barbara Pym. . . .