Definitely go more than once a week - go as many days as you can manage. Daily Mass is better if you can manage that. And perhaps work up to half an hour rather than 15 minutes.
Above all - consistency. Make a commitment to do the following things each day:
a) pray every morning and evening. Include a morning offering in the morning, a prayer to your guardian angel for help during the day, and grace before and/or thanks after your meals.
At some stage say an Apostle’s Creed, an Our Father Hail Mary and Glory Be, and a decade of the Rosary.
At night examine your conscience (look at the sins - and the good acts - that you did for that day). And say acts of faith, hope, love and contrition, followed by an act of Spiritual Communion and a prayer to your guardian angel thanking them for their help during the day and asking them to keep you safe during the night.
Add whatever other prayers you like, but not so many that you find it a chore.
b) Read as much as you can manage of either the Catechism or the Compendium to the Catechism (easier Q and A format - both are available online) every single day. These aren’t designed really to be read from start to finish, so you might just look at the index and dive into whichever topics interest you, whichever you’d like to learn more about. As well as maybe a chapter of scripture if not more (start with the Gospels).
If reading isn’t your thing you might prefer audio - apart from audio Bibles, there are some great audio shows at EWTN and great spiritual books available at other sites. I’m gathering you might be a teenager from your nickname - if you’re into sports at all there’s a great series they do called ‘Crossing the Goal’, which I’m listening to at the moment.