Ok, so I watched your match vs UTDZac's Peach, and here were my observations:
It was a pretty bad idea to run in at the start of the match and shield, even worse that it wasn't a light shield. You're really lucky that it didn't get poked at all during that big block string. You threw in some nice punishing bairs. You probably realized yourself that you should not CC against Peach. I don't know if you were possibly going for CC>dtilt, but imo, against Peach, it's not worth the huge damage you risk receiving unless you're at low %'s and Peach is at death %'s. As j00t said for your other match, you need to approach w/ fair less. Avoid jumping into Peach when she's on a platform above you; they just dsmash. :/ You're probably better of utilting or SH nairing under them. Also, I really think you should light shield more. It prevents poking and it gets you out of bad pressure. I noticed you also threw out a lot of attacks like fair, bair, and fsmash when the situation was at neutral (beginning of your second stock). You weren't punished, but the lag from those moves
is quite punishable. One thing you should work on is mixing up your ledge recovery game. You got up with ledghop fair quite a few times and some of those were punished. At 1:50, your shield almost got poked by her dair cuz you chose not to light shield (again), and it led straight to a nair actually
poking your shield, followed up with a dsmash. At 2:36, you threw out a nair and an fsmash, both of which could have been punished by the Peach from the close proximity at which she was floating (although, this Peach seemed pretty bad at actually punishing mistakes and following thru with successful hits). The last 30 seconds of the match were you monotonously using almost
solely fair with very little actual reward. I really liked your movement, though. Was real smooth. Nice match!