Magento announced they will stop support magento1 versions from June 2020. You can see more detail here.https://magento.com/blog/magento-news/supporting-magento-1-through-june-2020
Apart from these. There are some other benefits which can help you to make the decision.
1) Better Admin panel
If you see magento2 store you will see a drastic change in the Magento admin theme. It's a really cool theme with all menu of left sides. They have included more features in grid and sorting. Admin user can add more rows in grid without having technical knowledge. They can also add a field for filtering.
The performance was a challenging issue in Magento1. In magento2 Magento team improved performance and they have used the latest technology. Magento2's page loading speed is far better than magento1.
3) Testing Framework
Magento2 include testing framework so after development you can create test cases to make sure your functionality work as expected. A developer can write a unit test and automize testing for their own work.
4) Improved checkout
Compare to Magento1's checkout Magento2's checkout is very simple and it has only 2 steps. More faster and flexible compare to magento1 that will help store owner to increase conversation rate.