Just an FYI and not sure if you and the niece are in Iowa but Iowa does have an Inheritence Tax that affects non-lineal decendent heirs. Depending on how much the asset value is it can be a good amount of tax. A couple years ago I did one of these tax returns for a lady who inherited approx. $1.5 million of farm land from her uncles and her tax bill wasn't pretty.
There are a couple things you could do to avoid this though. In fact my client above was in the process for one of these things when the uncle died.
On a side note, you could gift her money why you are still alive. My wife's parents are doing that with us and her brother because they'd rather get to see us use it while they are still alive.