So I am wanting to get another barn, to fill up with show geldings. I'm almost at 100k, probably another week or so and I can buy a 25 stall. However, if I wait probably another IRL month, I could get the 50 stall. Should I wait? Or buy the barn, some geldings and save up again?

I'd save up till you can afford the 50stall or 100 stall

I would def wait for the 100 stall barn

I man kinda depends on what you'd want to put in the stalls. If I were to get another stable I would get a 50 For all my mares but I would keep my 25 for my boys since I don't show (yet) So I don't have many boys AT ALL. If you're a new player I think you should just save up for a 50 or 100 to full with loads of different horses. A mix of foals stallions and mares.

I've recently started a new side account just for showing. What I did was to get one more 25 stall barn just because with just 25 geldings it takes you ages to earn the 175k for a 50 stall barn. I rather had 50 geldings earning me money quicker. Once the 50 earn you money, get the 50 stall barn, but with only 25 gelding progress will be very slow.