Answer
You can make a Will if you are aged 18 or older, but you must create one voluntarily without being pressured by another person.
You must also have the mental capacity to understand the contents of what is being written in the Will and be aware of your assets and the people you choose to inherit your estate.
Once you have written your Will, you must sign it in front of two independent witnesses. All three of you should be in the same room during this process, as the two witnesses must sign the Will in your presence.