The honest answer: start where you can think clearly, then switch when speed limits you.
The trade-off
- Python — easy to read and write, great for learning ideas; but can time out (TLE) on heavy problems.
- C++ — fast and the de-facto contest standard; steeper syntax but rarely the bottleneck.
A recommendation by level
Beginners and most USACO Bronze/Silver work are fine in Python. As problems get heavier (Gold/Platinum), C++ avoids time-limit issues. USACO accepts both.
Learn the algorithm in any language; switch to C++ when the clock, not your thinking, is the limit.
See our Competitive Programming program and the USACO guide.