How tall are they, do they have branches/leaves yet? What medium are they growing in.
Peaches are mediterraeon [never been abroad, me
] so need shelter. They don't tolerate frost or cold. Not the time to put seedlings outside.
I use the 'coir'-type pots or rolled newspaper or toilet roll inners for seeds - making sure that the roots don't get broken eventually you could put one in each pot of your choice. The above will rot into the ground so no need to re-move. They would however probably prefer to be in a pot on a sheltered patio that can be moved inside in the Autumn.
Our plum has blossom :-).