In 1974, Anne McKenzie of South Africa ran 4:49.2 for 1500 meters at age 49. It was a W45 outdoor world record, which would stand 11 years. Now it looks like 55 is the new 45. On Saturday, 55-year-old Anne Gilshinan scorched a metric mile in 4:45.65 at an Irish Milers meet in the seaside resort town of Greystones, Ireland. The record she beat was only two weeks old — 4:48.65 by world champ Clare Elms in Tonbridge, Britain. As a 54-year-old, Anne took silver in the W50 1500 at Torun worlds, losing by only three-hundredths of a second (to…