Vaishnava Samhita. Ganga Yamuna Charitam. Vol II Book VI Chp 4 Shlokas 24 - 25

सुकुमर्यौ च सुन्दर्यौ किशोर्यौ च वरस्त्रियौ 
समर्प्य कृष्णपदयोः परमानन्दमाप सः  ||
अनेकजन्मरचितैः सुकृतैः प्राप्य केशवम्
कैङ्कर्यमिष्टं कुर्वन्त्यौ श्रीवने सुखमूषतुः  ||

He offered these good, youthful and charming girls of sixteen, at the feet of Shri Krishna and experienced untold happiness. Those girls reached Shri Keshava due to the merits accumulated in successive births. Serving Him to their taste they led a happy life.