Formal:
* Habari Kaitlyn, ukoje? (This is the most polite and formal way to greet someone)
Informal:
* Jambo Kaitlyn, uko vipi? (This is a friendly and informal way to greet someone)
More Casual:
* Kaitlyn, mambo? (This is a very casual way to greet someone you know well)
You can also use "Huendaje?" which translates to "How are you going?" This is a more informal greeting than "ukoje?" but still polite.
For all options:
* Habari means "news" or "greetings"
* Jambo means "hello"
* Ukoje? means "How are you?"
* Uko vipi? means "How are you doing?"
* Mambo means "things" or "how are things?"
* Huendaje? means "How are you going?"
The best option for you will depend on your relationship with Kaitlyn.