The "beware" reference is more directed at the low hour pilots rather than those who have been citabria trained. The aircraft behaves much differently when it has a couple of hundred kilos tied to its tail and if something goes wrong, you haven't had the exposure or experience to cope as well as, say, a 500 or 1000 hour pilot.
The citabria, being relatively low powered (compared to a 180) and a reasonably good main gear width to front/rear wheelbase length is a beautiful aircraft to start tailwheel training on. Fairly forgiving. I would suggest waiting a while to look at the towing, but you could do much worse than getting a TW endo this early in your flying. as mentioned, it promotes good rudder use, something that often needs work for tricycle only pilots (myself included when I started flying).
Kalavo,
RA can count towards the 200hr course, just not the 150hr CPL course.