You should probably get vanilla Minecraft stable before you start using Forge, so I would suggest looking through that debug.log and see where it crashes for what reason. 4GB of RAM should be more than enough to play Minecraft, so it's either configured incorrectly, or your machine cannot dedicate that much RAM to the game currently, which would mean you need to close some processes or you don't have enough RAM in your machine to begin with.
Regardless, the version you are using is no longer supported on this forum.
Please update to a modern version of Minecraft to receive support.
Currently supported versions are 1.19.4 (Latest) and 1.18.2 (LTS).