I'm on Windows 10, Java Edition.
I don't really know what is causing this but no matter what it keeps crashing even before the Mojang symbol pops up.

https://pastebin.com/j8y0nYqT

I have attached a copy of the crash report. Please help

Okay, where do I get the debug.log file from?

Also my forge version is 1.12.2 but I will reinstall anyways just to be safe.

debug.log file should be in logs directory. If it's not there, then your forge version is so old it has that file under different name.

1.12.2 is Minecraft version. Forge has many different versions and keeps being updated. Your forge version is 14.23.3.2655. Latest is 14.23.5.2823, recommended is 14.23.5.2768.Your version is from almost a year ago.

Thank you, it's working now.

Crash report isn't enough to say for sure what is wrong. debug.log file is needed for that.

The most likely case is that you have outdated forge and unsupported version of OptiFine installed together, so it crashes before forge can tell you that you need newer version of forge.