Hi there, you really have two options: to push that first A in the hope of getting a longer am nap again and then hopefully making her WU from that nap later in the day, so that she can get by with just a CN to BT without getting OT; or to keep the first A where it is but start capping the first nap, say, to 1h, in the hope of getting a longer pm nap. My DS found it much easier to settle for the pm nap with a capped first nap, and this became the first step of the 2-1 for him. He really needed that long pm nap to achieve a long A to BT without getting OT, or the nights suffered. So I personally liked the short am nap, long pm nap route, have a look here:
From 2 to 1 nap transition (10-12m and older)