Naturalization time frame

[beau]

i lived in Los angeles, had an interview for naturalization test since January 3rd 2018 , the officer gave me a letter that state congratulation my application been recommend for approval. Since then i haven't received any letter oath ceremony. ANybody know is it normal. I checked my status by use my A- number and nothing show it said invalid. is my status still okay? My friend went to interview 2 weeks after she already received her oath ceremony letter.

please help i am really concern.