Please solve the programming task below using a self-contained code snippet in a markdown code block.

Given an array of strings words and a string s, determine if s is an acronym of words.
The string s is considered an acronym of words if it can be formed by concatenating the first character of each string in words in order. For example, "ab" can be formed from ["apple", "banana"], but it can't be formed from ["bear", "aardvark"].
Return true if s is an acronym of words, and false otherwise. 
 
Please complete the following python code precisely:
```python
class Solution:
    def isAcronym(self, words: List[str], s: str) -> bool:
```