We(Nashville Rugby) played the St Louis Ramblers yesterday, good bunch of boys, they gave us a much better match than we expected. Still a victory for us though.
If you can hang "as Rx'd" on most WODs, you should be in pretty good shape for rugby. Its kinda getting toward the end of the spring season right now, go ahead and get started, play through the summer 7's season as well( 7's is 7 men per team Vs the usual 15 man a side game, played in the summer here, lots of fun).
Also see if they have a summer Touch rugby program. Its a good way to learn the game, and get some good runs in. Unfortunately you pick up some bad habits related to the full game, but it is still a lot of fun.
You sound about the right size to be a lock or a flanker. And a lineout jumper most likely at that weight. Let us know how practice goes.