The pouffy sleeves, slightly blouson bodice, and waist band with down turned waistline and silhouette suggest 1899 is a better date. The sleeves would have been slightly raised and the dress would have had a striking hourglass figure in 1889 (see her 1891 honeymoon portrait and this portrait).
Keywords: Smeichen, Margaret Helen Anderson, Margaret Helen Greville, Greville family, British, frizzy coiffure, head band, bun, bodice, U-décolletage, lace bertha, quarter length full sleeves, arm bands, lace flared cuffs, waist band, bows, down turned waistline, close skirt, fan