Am I Paying To Much... Should I be Concerned

[Cheyntarie Washington]

Ok, I found a property for 24k (reverse mtg situation) it's the oldest house on the block all other homes are newer 90k habijax homes and are well kept on quiet tucked away street. I found myself in a multiple offer situation. I offered 40k which was accepted. Property will require 8k Rehab at most but I'm concerned about actual value, comps today show 42 to 50k ARV. I'm required to put 4k earnest down.
I have a 10 day inspect. period but contract states "Buyer(s) participating in a highest and best, multiple offers situation understand that any special consideration for concessions, repairs or switch from cash to financing may result in seller terminating this agreement and retaining buyer’s Earnest Money Deposit." My questions are... does this mean if the as-is appraised value comes back much lower than offer, I would lose my deposit if I request price adjustment based on actual value? Also, house will easily rent for 800 a month. This is the worst house on the block but solid concrete block home with original wood floors. Should I care about not having equity initially?