There won't be any issues.
By default - that is, if Windows Setup sees no partitions on the harddisk - it will create a small 100MB system partition and a larger one to install itself into. The system partition then holds a few boot files needed for Windows to start.
The advantage of this scenario is that you can install other operating systems in logical partitions, which will all boot via the system partition.
In your case, the boot files simply share the same partition with Windows. There's no disadvantage, except if you install other Windows versions separately, they'll place their boot files on your current Windows partition.
Anything within Windows (updates, system restore, etc.) is not affected at all.