If you think that she would benefit from a preschool environment, on a part-time or daily basis, conduct a personal investigation of the best in your area and give it a trial run. Don't think that because all you see in a preschool is "playtime" that there is no learning taking place. Toddlers learn best and are most intellectually stimulated through play and play-like activities rather than formal instruction. Educational psychologist Jane Healy cites recent brain research suggesting that the more kids move their bodies, the more they stimulate their brains. Healy says, "When you stimulate the cerebellum [through exercise], you make your child smarter." In addition to preschools' providing ample opportunities for kids to achieve this body movement/cognitive development connection, they can provide youngsters opportunities for social competence and encourage their zeal for learning. Unfortunately, many preschools have become more like kindergartens, emphasizing academic skills and accomplishments. David Elkind has documented this disservice to children in his book, Miseducation: Preschoolers at Risk.
For more detailed scientific information on brain research and how parents can use these findings to promote readiness in their kids at home, I suggest that you read Jane Healy's superb book, Your Child's Growing Mind: A Guide to Learning and Brain Development from Birth to Adolescence. Keep up the great work providing your little one the attention, love and stimulation she needs for her overall growth and development.