Yes you're going to have to talk before engaging in sex again. Or start out by saying...you know last time we did A,B & C...would you want more of that? Less? What direction do you see this going?.....
Then hopefully she'll b honest enough to tell you.
Rough sex is a broad term. So are you basing this on what she can stand physically? Stamina? Position? Thrust level? I'd say you'll have to see find those boundaries together or someone will be injured. Rough sex has a wide spectrum depending on the individual.