I understand your situation very well as I used to walked in your shoes. I dated a guy 18 years my senior for 3 years. During this time we never have a fight and trust me I do try having a fight but since he is more mature, he can handle relationship very well.
It was love at first sight and my real first love. However, I ended it as our time was different. While I wanted career, travelling and enjoy the youth, he already did it all and wanted family. It was heartbreaking for both of us but turn to be the best. He is now with someone he loves and so do I.
Despite all heartache and pain, if you think he might be the one -go for it!! You never know what this relationship entails and it might turn to be best thing ever. Don't give up before you start and good luck.
It is up to you, no one can give the right answer.
Good luck ka.