Not sure what to do re Music lessons. Piano, Trombone or Singing?

[FiveHoursSleep]

DD2 is 11 and is going into Y7 at a school that has a good music program in September. She plays the trombone and piano already ( Grade 3 in both) but really loves to sing.
She has always had a nice voice but we've recently had people telling us that she should have lessons. She has sung in choirs and school productions all the way through school.
The trouble is, if she did have singing lessons, she would have to drop one of her other instruments. We don't have the money for her to do three and she won't have the time.
Piano is good for general musicality, trombone good for playing with others (orchestra and band) and singing is what she LOVES to do.
WWYD?

I'd keep on with the piano and trombone and let her sing for fun only.

I would too. She can always have singing lessons later on.

Keep the instruments. Trombone will teach her breath control and intonation anyway.

(I never had a singing lesson and won a choral scholarship to university).

Find a singing teacher like me who will teach her occasionally, maybe just in school holidays? It's not necessary to have weekly lessons

Noteventhebest- where are you?