I know that diapers may be expensive, not to mention that it is just more convenient to have a potty trained child, however...
if you wait for your child to tell you that they are ready, it will be much easier to potty train. DS was over three (yikes) and DD was 2 1/2 when this happened, but they each approached me and said they wanted to wear underwear and that was the last day they wore diapers during th day. DS went through about 7 pairs of underwear that first day, LOL, but he hasn't had an accident since. He never even needed a diaper at night. DD still needs to wear a diaper at night as it is still pretty wet when she gets up in the morning. She is not yet 3.
I had a potty chair in the bathroom that we talked about and we had some potty training books that I read, but I never forced them to sit on the chair or anything. Just kind of introduced the concept and let it go. They were literally potty trained in one day when they decided that they were ready for underwear. Just have some ready fo her. DD asked me about underwear out of the blue one day. I totally wasn't expecting it.
IMO, the biggest hurdle to overcome in potty training is the pressure Mommy gets from friends and family about the issue. But, if you let your children take the lead, it will be a lot less stressful for everyone.
HTH, sorry to get preachy, but this is one of those developmental things that I feel strongly about, LOL.