My mum minded my oldest DD until she went to preschool and school and her socialisation was fine. She died when my 2nd DD was 2 so DD2 had a variety of carers and she is much more clingy to me because of it but then again its more her personality too.
If i had the opportunity I would leave my little one with my mum (provided she followed the same sort of parenting style as me and upheld my routines) then put them in preschool when they are 3 to socialise.
Having said that DS has been in FDC since he was 8 months old and loves it.