Logic seems correct. To verify whether a language is context-free, you can use the pumping lemma for context-free languages. This states that if a language is context-free, there exists a number p (the "pumping length") such that any string s in the language with length greater than p can be written as s = xyz, where |xy| <= p, |y| > 0, and for all i >= 0, xy^iz is also in the language.
If we apply the pumping lemma to the language L, we can see that it does not satisfy the conditions of the lemma. In particular, it is not possible to pump any string in L to obtain a longer string that is also in the language. Therefore, L is not a context-free language.