Congratulations on you preparations to enter the Church. I think that at age 14 you should not be considered a child any more, you are an adolescent. Adolescents, in their enthusiasm, some times may go overboard in matters such as these. The things you have planned do not seem too much to me. Since you are not yet a Catholic, you are not required to do anything, but I am sure that our Lord is pleased with your wanting to unite yourself with His Church in her preparation for Easter.
Catholics from the age of 14 abstain from meat on Ash Wednesday and the Fridays of Lent, but fasting is only required of those between the ages of 18 to 59. Fasting from food is not recommended for those under 18 since our Mother the Church recognizes that young people are still growing and need nourishment.
Your plans for giving up sugary drinks, and adding some prayer and spiritual reading to your routine are great. They will not be so heavy a burden to you that you get discouraged and give up, and they won't get in the way of your school work and usual helping around the house. The Lord does not want us to do anything that interferes with the duties of our state in life, in your case, school work, and helping your parents at home.
Your plans for Lent seem appropriate for someone your age and in your situation. After such a good Lent, I know that you will experience the joys of Easter in a way that you never have before. Our prayers are with you on your journey.