My son went five days a week from just before 3 1/2. He was fine, but by the time he finished he was quite bored with the routine. With my daughter I probably won't put her in full time. We didn't have a choice as to what time of day his session was, so can't help there. He went morning and that was good because it is like going to school and prepares them for the quick morning routines to come.
My neicetarted doing 5 afternoon sessions at pre-school just a few days after her 3rd birthday and coped really well. She was VERY ready for reception after two years of it!
Personally I would prefer mornings simply because I always feel afternoons only take up the entire day.
My DD1 (aged 2.10yo now) started at pre-school 2 months ago oing two afternoons a week and has loved it. However, as the session starts at 12.30pm it means getting lunch over with before noon so that we have time to walk to pr-school.
That said, morning would have had their issues too as DD2 is only 6mo right now so being up and out by half eight a couple of months ago may have been a challenge too far for me!
DD1 is signed up to do 2 full days from September. I have no worries about her coping. She was 2 months prem and has coped with every challenge along the way. Goes to CM 4-5 days a week for up to 9.5 hours each day and is full of energy - right up until she falls fast asleep as half seven each evening!
Pre-school is lots of playing - I have spent several sessions there with DD1 recently and was involved with it when I worked at the attached primary school. I imagine your DD will love it!
As a parent, I think mornings are much better. Gets them into an 'up & out' routine for school, and they've still got time for a nap / rest / chill out time after lunch which is important for a newly 3 y.o.
However, if you take the afternoon, the preschool administrator will love you forever because it's notoriously difficult to fill those sessions!!
I prefer mornings as you then have the afternoon free. DS has got a morning place for when he starts in January (is 3 in October) and it will fit in with the school drop off time for dd too. Afternoons would have been trickier as the nursery would finish 30 minutes after school finishing time. DD went 5 mornings from the age of 3 and coped fine. DS will be doing 5 mornings too.