Yes you can, even with an auto...You can top something that small???
Alaskan Purple auto- started life as a mutant, so I cut off the mutant parts and was left with the first two leaves and 2 tiny growth points...IIRC, it was 12 days old.
Here's the same little mutant auto a few months later-she recovered from the topping pretty well...
So yeah, you can top something that small , babygirl!
Sorry to clog up your thread, GDB, but I had to answer that question