Can you date someone significantly( let's say at least 10 years) older or younger ?
There are many Christians who believe you cannot even date. In other words, they make a distinction between casual dating and courtship which is purposely only dating people you see a potential future with (marriage material).
If we read the Bible carefully, then I think that we can pretty safely conclude that God is okay with marriages where the couple are more than 10 years apart in age, but we need to practically consider some potentially negative affects of such a union.
For example, although none of us know the time of our death, if the husband is substantially older than the wife, then he might wind up dying first. If he is the sole or main provider for the family, then that could be an issue. Also, if there are any children that come out of that marriage, then they might lose their father at an early age if he is substantially older than their mother.
On the other hand, if the wife is substantially older, then she might lose her ability to bear children when her younger husband might desire some or more.
Also, if the marriage is based a lot on how your spouse looks, if he or she age quicker, then the eye of the younger person might start to roam.
I know that you mentioned dating and not marriage, but if you are dating with the hope of marriage, then these are some practical things to consider, and the examples that I gave are by no means exhaustive.