Workout Routine Help

Hey ladies, alright so I hope someone can help.

I've been gyming for the past few months and I have definitely seen great results, but it seems like I have hit a plateau.

I am no longer getting sore the next day and I think it's time for me to change up my routine?

On a Monday I usually lower body, Tuesday l do upper body, Wednesday rest. Thursday lower body and Friday upper body Saturday and Sunday rest.

I have felt this works really well for me because otherwise I complete my workouts way to fast and I'm left not knowing what else to do.

For legs I do - leg raises, leg press, I work out my inner and outer thighs, calve raises, hamstring curls, curtsey lunges and usually another bum workout where you kick back.

For arms I do - bicep curls, hammer curls, lateral shoulder raises, pulling the bar up to my chin and lowering it , shoulder press, tricep "pull downs", front shoulder raises , and then I use 2 back machines too. One where I pull down and one where I pull backwards. (Can't remember their names)

I do 3 sets of 12 reps for each workout and I work abs every workout day.

Please any tips or advice would be appreciated. I build quite fast as well.

How can I change up my workout?

Sorry that it's so long, thank you :)