I have a 3mo old apricot tree that I have grown from a seed off of the old tree I have on property elsewhere. However the tree sprouted with two main trunks. I ended up planting this tree in the backyard of my home next the a fence. Since Im new to the whole gardening and tree stuff I am wondering if I could pick the strongest of the two trunk to keep and cut the other one down by the base? Or should I wrap them tightly together and see if I can fuse them together? If so when should I do this? after the first winter or as soon as possible during this current first summer while the tree is still flexable? 

I want to train this tree into a dwarf type pyramid tree for a small backyard. any info is appreciated. Thanks