Honey, we are here for you, but weaver is totally right we can't see your LO so you will have to trust your instincts, we can support you but you are mummy and you DO know best, even if it feels terrifying to think that way.
We are just mummies too and although we have been through tough times with naps too and may be able to offer our thoughts from our experiences, you will need to make the choices as to what works for you and your DS on a day by day, nap by nap basis.
We have suggested that you stick with the 3hr15mins A time for a few days and then you will hopefully be able to say whether you need to pull back that first A time a bit. One more day to try it and then see what you think.