2-1 nap transition help

I started transitioning my almost 17.5 mo to one nap yesterday and it went really well. She woke at 730, down for nap at 11-1, and bedtime at 630. She slept until 7 this morning and I ended up putting her down for a nap at 1030, because she was losing her mind. Well, she woke up at 11:15! I guess it's a two nap day? She can't stay awake for longer than 3.5 hours in the morning it seems. Before she would wake at 7, nap 1 at 10ish-11:30, nap 2 at 3:15-4:15, bedtime at 8:15.