.net core vs express+nodejs

Question

Hello all, I am junior dev and I am working on Winforms and WPF for maintenance projects. I want to switch to web development, and I want to choose a backend technology to switch my career path. Although i have 1.5 experience in C#(actual work experience) and some decent knowledge in javascript and a bit of Angular(by doing side projects) , I am in a dilemma to go for asp.net core or mean stack. Please give your valuable suggestions. Please note: I currently don't have any knowledge in asp.netcore mvc and I am just thinking whether it's worth to learn thinking of the long game or to be with Javascript and play it safe.