Preschool advice - PLEASE !

My son just turned 4 in November. He’s in a half day preschool program at our local elementary school right now. It’s 4 days a week and he gets on the bus at 8am and he dropped off by 11:30. So, he’s only gone 3.5 hours.

He is very shy and preschool has been a big adjustment for him. At the beginning of the year he was crying some in class, would only whisper to his teacher, wasn’t playing with the other kids and just all around was having a difficult time.

It’s been 4 months and he is finally participating in big group activities, talking to his teacher and the assistant teacher but he still prefers to play alone and needs A LOT of encouragement to play with his peers.

I have to make a decision about next fall by the end of January. My choices are to put him back in half day with the same teacher or to put him in the full day program. The full day program is 5 days a week from 8:20 to 3 so double the amount of time and double the amount of kids.

On one hand, I think he should do full day because I feel like he needs that experience and exposure before kindergarten.

On the other hand I can see him benefiting from half day as well.

Whah would YOU do if you were me?