Age gap
Friends in the workplace are a great thing to have, they can help you out with your job if you need a favor and are great companions during lunch. There are no rules as to who you can be friends with at the workplace and often large age gaps occur between people.
You will often see people who are ten or even twenty years apart in age hanging out and having a good time. There is no weirdness to it, they are both in the same boat and are just enjoying each other’s company while at work. Also, age is just a number, a lot of older people are still really hip.