Note that the "take the first codepoint" approach doesn't work for all languages. Take Hindi for example. This is a name:

    प्रेरणा
    'preraṇa'

The convention for initials in Hindi is such that this would be the "initial":

    प्रे॰ (< प + ् + र + े + ॰)
    'pre'

which is the first four codepoints combined (because they are in some sense considered a single character) plus another codepoint!

If for some reason you needed to respect locale-specific initialism conventions for a lot of different locales, it might be worth introducing an abstraction for determining the initials of a name.