It would be wise to check the chain wear with a chain "stretch" gauge and replace it if the chain is beyond 0.75 or 0.8. Re the rear sprockets, they're only likely to be a problem if the current chain is worn beyond 1.0 stretch.
The other thing to worry about is whether the derailers can simply handle the difference. The rear derailer has a "tooth range" in terms of the greatest difference between the sum of tooth counts of the largest sprocket pair and the smallest, and if that range is exceeded then the chain will either go slack on the smallest combo or become over-stretched on the largest.
Further, the front derailer has a limit to how great a tooth difference it can handle, and too much difference could result in the chain rubbing the derailer or iffy shifting.
But these problems are only likely if the difference in old and new ring diameters is substantial.