Expect that it will take her a few times to really get comfortable on skates. She might surprise you, but if she hasn't skated before, chances are good that she's not just going to take off after a short stint on the ice. If the rink where you are going allows kids to use milk crates, let her use them. A lot of rinks don't allow them. If the rink doesn't allow milk crates, then expect that you will start off hunched over uncomfortably as you hold her up, then she might be able hold on to the boards and shuffle along, then perhaps have one hand on the boards and another holding your hand while she moves slowly around the rink.
My kids all play hockey and they either started late (my oldest was 9 when he learned to skate so it took about an hour before he could move on his own) or really early, as soon as they could stand. Typically the brand new learn-to-skate kids need a couple of hours of ice time (two complete sessions) before they can stand without falling and move forward without crashing.
Have her wear snow pants, waterproof mittens and a bike helmet so that when she falls she's not afraid or uncomfortable. Really as long as they're not feeling cold or wet, most kids are fine with falling over and over. It's when the gloves get soggy and their fingers get cold that they stop thinking it's fun.