Dan,
Thanks for helping to brighten up the dog days of winter by posting.
I hope you enjoy racing your O 25' this coming season. We race against an O 25' at our club Weds. night PHRF races. They are pretty competitive with us and the skipper is old and wise so we are always on the lookout for him.
I assume your club would use PHRF handicapping. Around here the O 25' gets a PHRF around 248, while our Tartan 27' gets a 240. Ratings this high mean that our boats are not considered fast or competitive but we still enjoy the race. Simply put, that just means that we have to beat him over the finish line by a minute or two to actually beat him on corrected time.
The best advice I can offer is to just stick to it (the racing) as you will learn a lot and your finishes should improve over time. I also recommend taking other racers along as crew so you can learn from them. Another item I'll mention is that you need a decent sized jib on the O 25' to make it sail more competitively. My friend with the O 25' sailed his first season with the small jib his boat came with and did much better the second season with a new larger jib.
Stay warm.