The fact that you are 27 means that you will need to eventually address the problem that you have no second molar in the position of tooth #31 because you have a long life ahead of you and the opposing tooth will supraerupt.
Do you need to replace the missing #31?
No.
You can function perfectly well with your first molars as the last molar.
Will you have to extract the opposing tooth once it supraerupts and starts to create problems and discomfort?
Yes.
Is it worth it to replace #31 with an implant?
You have all the information you need to make a decision, but ultimately, the decision is yours.
Good luck!