How quickly can you get the first element from a linked list?

In a linked list, the first element is accessible in constant time O(1), since the list usually has a reference to the head. To get the first element, it is enough to refer to this reference.

Example in Java using LinkedList:

LinkedList<String> list = new LinkedList<>();
list.add("First");
list.add("Second");

String first = list.getFirst(); // O(1) operation
System.out.println(first); // Will output "First"

If you implement a linked list yourself, typically there is a field named head in the class, pointing to the first node, and access to it is instantaneous.