Since you like the idea of MUni and have local trails I would say go ahead and get the 24" MUni now if you can afford it. If you’re planning on doing a lot of riding on pavement you might want a tire that work better than the Duro Leopard that comes with the MUni. You could get a 24" Maxxis Hookworm to use on the street and keep the Duro for trails. Another option is to go with a tire that can handle both street and trail like the Felt Berm Master.