Your computer has to install some programs and then build everything from source. This is going to take a while depending on your computer speed. Patience is key. We can't speed it up for you. It may look like its frozen but it is not.
node-gyp (used to build better-sqlite3) is not compatible with Python 3. Yes, it's been 10 years since 3's release. Yes, it sucks. But you need to have python 2.7.x in your path to install better-sqlite3. If you're not using python anywhere else, uninstall it and make sure to follow my installation instructions. If you are, run
npm config set python python2.7 before running the install again.