Deep learning techniques have a potential in allowing fast deformable registration tasks. Studies around registration often focus on adult populations, even if there is a need for pediatric research where less data and studies are being produced. In this study, we compared three methods for intra-subject registration on publicly available Calgary Preschool dataset. Using the DeepReg framework, pre-registering with a rigid and affine transformation (proposed RigidAffineReg method) showed the least negative JD values and the highest Dice score (0.924±0.045). By achieving faster alignments, this tool for pediatric MRI scans could help proliferate larger scale population research in brain developmental studies.