With access to devices and online platforms at an increasingly younger age, it is essential to protect children from potential online risks. In our studies, we particularly focused the parents who have a child under 13 years of age. To this end, deriving from developmental psychology, we base our low-fidelity prototype design (termed as 'treatment') on a set of design principles focusing on open communication, instilling self-regulation, and availing granularity along with designs of existing Google's parental control as a baseline. First, we conducted semi-structured interviews with 21 parents to understand their perceptions, including suggestions for design improvement within our prototype. Then, we conducted an online study over MTurk with 156 participants to compare and evaluate the treatment condition against the baseline in the realm of our design principles. As reflected in our results, parents appreciated the insights into the children's activities to have a meaningful discussion with them, the significance of nudges in instilling self-regulation, and the usefulness of granularity in a wide range of contexts, including shielding the children from inappropriate content and defining purpose-specific device usage. The findings from our studies lead to the recommendations, and the guideline for future research in the sphere of developmental parenting and inclusiveness.