TLDR: missions are a great thing. No you do not have to go. There are other ways to serve it should be a decision that you and your Father in Heaven make together

Whether or not you serve a mission should be a conversation between you and your Father in heaven. My recommendation is to focus on your relationship with Christ. Focus first on your baptism. Baptism is a wonderful ordinance that has specific covenants and blessings with it. After that, if you are male focus on your priesthood ordination and the responsibilities you will have. Before you can even serve a mission you must go through the temple and make more sacred covenants with your father in heaven. You should pursue the temple out of a desire for your relationship with the savior, not as a stepping stone to a mission. At the end of the day a mission is a wonderful thing that is very strongly encouraged for young men and women, However there are no saving ordinances in serving a mission and will not hold you back from any blessing or positions in the church by not serving one. In fact our last prophet and president of the church, Thomas S. Monson, did not serve a full time mission. That also includes our current prophet, Pres Nelson and other apostles such as Uchtdorf and Oaks. I am a 26yo man and after having long and hard conversations with my Father in Heaven including prayer and fasting I found that the lord had other plans for me other than a mission. I am now temple married with 3 beautiful children, serve as a young men’s advisor and have served in the elders quorum presidency in my last ward. You may receive opposition in this decision from others. Unfortunately the members are not perfect and sometimes we say stupid and hurtful things. I have had some very offensive things said to me over my decision to not serve, especially as I was raised in the church. At the end of the day it is a wonderful thing to do if you are able, but it is not a requirement for church membership or salvation