I wouldn't. The transition from practicing on an upright (which typically have weaker actions and easier control over the sound, as there isn't a lot of it) to a baby grand, despite how small it may be, is never seamless.
Learning to play on it and have the same outcome as with an upright can be a hard task.
This is a crock of ****. I play mostly uprights, I can't outrun the action on the ones I own. Would >192 bpm suit you? That is with the fingers of two hands alternating on one key.
Nor do I have trouble playing either loud or soft consistently. No, I don't own a Whitney Lion or Winter, those are only furniture. I own Steinway & Sohmer consoles. Other pre 1990 quality uprights are Baldwin, Mason & Hamlin, Chickering, Everett, Kawai, high end Wurlitzer. Inspect 39" or taller pianos, shorter spinett pianos have a slower drop action. Many of these consoles are going to the dump after listing for <$100 because people want electronic entertainment, not an instrument. There are some pre 1930 brands built from kits that have superior actions, for example Knabe. The problem with the better pre 1930 44" uprights is mainly the weight when moving; they are 100-150 lb heavier than a post WWII studio even. These old ones have to be inspected carefully, there was a lot of **** sold then, especially the many surviving former player pianos. Don't drive out to see anything with a door for the piano roll.
I've never played a baby grand I thought sounded good. They are mainly for show, IMHO, "look I'm a piano player".
If you're going to perform on stage on a grand, by all means buy a grand to practice on, one with a heavy action. That applies to all 300 performing classical pianists in the world. Pop pianists play on simulated grands with electronic action these days. The better to exercise the electronic PA system without amplfying the footsteps. All the halls I perform in, have console or studio pianos.
There are many good sounding grands over 6' , but most of them have actions that are too heavy for my native Am. forearm muscles. I could play my teacher's Sohmer grand when I was 15, but as my muscle strength declines in my sixties, I'm glad I bought quality uprights.
Besides unique appearance, the main feature a grand has that an upright doesn't, is a middle pedal that sustains only those notes down when it was applied. Not much literature requires this feature. And not all grands have this feature.
Enjoy your shopping.