Thank you everyone for the replies! I have some thinking to do. Part of me would love to get ahead of my kids, but on the other hand, realistically, it would probably work out better to just learn with them. I imagine myself getting started but not following through when things get busy.
One other question, those of you with kids spaced fairly close, how did you teach Latin? My kids are each two years apart, so my thought was start ODS around third grade and then YDS two years later when he is in third grade. Then again when DD is in third grade. Is this a good way, or would combining be better? I don't want to hold ODS back by waiting for YDS to catch up, but I also don't want to go crazy keeping up with three kids in three different places. I know I have a good while before I really need to worry, but my mind wonders this stuff anyway :-).