Oh, I understand now.
My brain just doesn't work well sometimes.
The monsters aren't too bad usually, but I can understand your concern. I found that changing the gamerules helped me a lot:
/gamerule keepInventory true
/gamerule mobGriefing false
These commands greatly limit the damage hostile mobs can do, since the first one means you never lose your items and the second one keeps creepers from blowing holes in your home. With them set up, you can practice fighting mobs without much worry.
Or you can continue to play peaceful mode, because that's a lot of fun too.