It is certainly a good idea to learn Assembly language, preferably of several different processor architectures. However, C should be learnt first.
The reason for that is that people who dive right into Assembly, tend to write sub-optimal code because they don’t understand well how this code is executed by the processor and how to compile it. This is while programmers who’ve learned C are better equipped to understand how Assembly code works, because it is somewhat more convenient yet still very close to Assembly.
A friend of mine reported that in his workplace, where they write Assembly code for various Digital Signal Processors (DSPs) some of the native Assembly programmers order their instructions in ways that are executed inefficiently because of the special processor pipeline. He then told me that C programmers who learn Assembly make better Assembly programmers.