I cannot answer this question, because the answer depends a lot on which type of heart malformation you have. Congenital heart disease (meaning heart malformations you are born with) is a very large and complex area of cardiology, and there are multiple potential malformations that could be going on. Some of these are very simple to fix (such as an atrial septal defect, which is the most common form of congenital heart disease not diagnosed until adulthood), whereas other adults with congenital heart disease may have already had heart surgery
as babies or children and continue to need periodic interventions over the course of their lives. Additionally, depending on what kind of repair is done, complications can develop. For example, artificial valves and tubes may become narrowed or become infected by bacteria, requiring further surgeries.
Your best chance of getting all your questions answered is to set up an appointment with your congenital heart disease specialist and / or the surgeon
who is planning to perform the surgery. They will be able to give you a better sense of what they are thinking as well as a better sense of what they expect to be the long term effects and consequences of the surgery.