St Exupery's Quote translation

Hey hey everyone, i'm trying since few weeks to translate the best possible i can, a quote from Antoine de Saint Exupery (Author of The Little Prince) in Quenya.

I got myself books and also few websites to help in my research.

The quote is : "All grown-ups were once children but only few of them remenber it"

From now on, i could manage to have the following sentence =

ilya olinwa náner hína apa nótime imíca tar renië

can some of view help me and give me advices please, just to let me now if i got the right words and stuff ?

That already looks quite good! A couple of points though:

• You need to make "grown-ups" and "children" plural: olinwar, híni (usually we would expect *hínar but híni is a special case). Since ilya is an adjective modifying olinwar we need to pluralize it as well: ilye olinwar. In náner you already have the plural agreement.
• As apa already means “after (of time)” and “touching, against, on (above but touching)”, I prefer to use mal for "but".
• tar looks like you intended it as the plural of ta "that", however the form should actually be te "them".
• renie is the gerund "(the action of) remembering". Here you can simply use a normal conjugated verb form ren- > renir or not using a neologism enyal- > enyalir. Then you still need a direct object "remember it" for which I'd suggest sa.
• Your left out "once" and "only" for which I suggest néya, rie.
• optionally you can elide vowels that can't form licit clusters like e-i, e-e (but not e-o which occurs in words like Eonwe) for better flow, compare how lúmenna is elided in elen síla lúmenn' omentielvo.

Ilye olinwar náner néya híni mal rie nótim' imíca t' enyalir sa.

Wow, a huge thank you ! I wasn't expect this sentence rightly written so quickly.

So thanks to you i realized i forgot a lot of conjugation and grammar !

I now understand my mistakes and oversights, i will continue to learn i like this language even if its rare to talk in Quenya irl i have to admit