Hi Glen,
The Umarex 92FS is quite a meaty pistol in the hand, when compared to the likes of the 1911, but would certainly be a more realistic introduction to handling the kind of double-stacked magazine pistols in use in modern law enforcement. I have a pair of 92's; a black model with standard plastic grips and a nickel model with wood grips. Firstly, the nickel with wood looks very sweet , so if you're after something to please aesthetically, then I can recommend it! As an aside, I shot a 9mm 92FS when we still had firearm pistols in the UK, and to my recollection, the Umarex Beretta 92FS actually feels a touch bulkier and heavier than the real thing.
With regard to the grips, the wooden ones have a much more defined chequering pattern to them, which tends to help the tactile feeling of 'grip' on the gun (especially if you're getting a little sweaty-palmed in competitions). However, they are noticeably wider than the plastic grips, so make an already pretty chunky handful into quite a hefty feeling pistol in the hands. Personally, I don't regret getting the wood grips for my nickel 92 as the improvement in grip 'feel' (and the visual appeal!) is worth it - but the black plastic grips are perfectly fine otherwise. Maybe get the nickel with black grips and then you can always order the wood grips as an extra if your daughter feels she can cope with a slightly chunkier grip... If you're going for something to provide a taste of the experience that she'll get with a service issue pistol, then these would generally be black/blued with plastic/poly grips anyway!
It also maybe worth a consideration that the new matte black finishes are not as durable as the old gloss black models (I've had my old gloss black 92 for over 10 years now, and I can tell that the new ones aren't quite as resilient), so the nickel model may be a longer-lasting finish. Certainly more bling as a present to your daughter!