Not at all really. Russia is now a ‘democracy’ and not the USSR you remember. Even if the good 'ol USSR was still around and kicking they never did get along very well with China. In fact, the border between the USSR and China was very heavily guarded.
Certainly both countries viewed the US as enemy #1 but they were a close 2[sup]nd[/sup] to each other. They actually practiced different versions of Communism that were only marginally more compatible with each other than they were with Capitalism.
For the USSR it was hard to be comfortable with 1 billion people antagonistic people on your doorstep. Even with improved mass destruction devices that would be VERY hard to stop. China always felt the USSR was holding out on them keeping them from the good stuff as well as anger at having to play second fiddle to the USSR.
Today things are FAR different. I seriously doubt Russia would do anything if China and the US got into a tussle over Taiwan. In fact, they’d probably enjoy the show. Russia might only care if we actually invaded China and that would be REALLY stupid on our part.
So, no worries on that count. You’re girls are safe in this regard (at least, I think there are many other more likely threats to sweat over than the US and China nuking each other).