Happy New Year!
If you have made a New Years Resolution to go the the gym 3 times a week or run a half marathon essentially this is a great idea! However just remember not to go from 0- maximal training, as you may end up with an injury. Pay heed to the 10% rule. ie don’t increase your weekly mileage by more than 10% of what you did in the previous week. Also make sure you have a decent pair of running shoes and that you keep your self well hydrated with water. Copious cups of tea and coffee aren’t the same!
Good luck with your challenge for 2018!