Yeah my house 5.30 can be a commen time to get up. BUT mainly during season or developmental changes. She probably is ready to drop that second sleep. Matilda & Jovie both went to 1 sleep at 13 months. The past few mornings we've been up with the sun because we cut some trees down outside the girls room & now they wake with the extra light.... bummer.

A good way to start doing it is to keep her up for a bit longer before her morning nap if possible... everyday push it back 15 minutes or so and soon she'll be sleeping from midday to 2 or 3 or something & her night sleeps will settle down.