What are your reasons for sending her? are you planning to return to work, or do you think she needs socialising, or do you need a 'break' day so you can do errands etc? If it's not for a work reason, I wouldn't worry about sending her for reasons of socialisation, because that this age they don't need it, nor do they gain anything from it really - children are much much older before they truly start to interact with their peers. If you think it is going to upset her and can already picture her crying when you leave her, then I think you've answered your own question.