Issue with opening Minecraft 1.7.10 with mods in it.

I have Minecraft Forge 1.7.10 - 10.13.4.1614. I have 13 mods active and I was playing just a day ago when I was going to re-launch Minecraft so I could play again. The issue was I kept getting something like:
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release
[14:16:48] [main/INFO]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker
[14:16:48] [main/ERROR]: Unable to launch
java.lang.ClassNotFoundException: cpw.mods.fml.common.launcher.FMLTweaker
at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[?:1.8.0_121]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_121]
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[?:1.8.0_121]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_121]
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:106) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_121]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_121]
at java.lang.Class.forName0(Native Method) ~[?:1.8.0_121]
at java.lang.Class.forName(Class.java:348) ~[?:1.8.0_121]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:98) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
I don't know if it is an issue with forge, which I do not know how to fix or if it is with Minecraft.

But I then tried updating my JAVA launcher and still, it crashes.
(I'm also ultimately unsure which version it is. I am on Mac... but I don't know)

Thankyou!