You are correct that Delaware and Pennsylvania are both part of the DLC (Drivers License Compact). This Compact requires member states to report traffic offenses back to the state in which the driver is licensed so PennDOT will be informed of your DE speeding ticket.
As you stated a speeding ticket in Delaware for 20 MPH or more over the posted limit is a 5 point offense and may also lead to additional actions including suspension of driving privileges according to the DE Division of Motor vehicles violation points list. Though for your rate of speed, 23, it appears just an advisory letter is likely to be sent once you are convicted for speeding 20-24 MPH over the posted speed limit.
In Pennsylvania exceeding the maximum speed limit by 16 to 25 mph is a 4 point offense. However, according to the PennDOT Driver's License Compact fact sheet (found at www.dot10.state.pa.us/pdotforms/fact_sheets/fs-dlc.pdf), minor offenses occurring out of state, such as speeding, will not appear on your driving record unless you are a commercial license holder and points will not be assessed to your PA driving record.
Free Auto Insurance Quotes
[Let CarInsurance.com help you find affordable auto insurance now.] If your auto insurance rates will be affected will depend upon if your insurance company does a comprehensive motor vehicle record search and sees this out of state offense. If they do, than depending upon the insurance carrier's rating system you rates may be affected. Without knowing your specific insurance company's rating system we could not say if this ticket would significantly change your premiums.
To find out about your insurance provider's rating system you can request information on it from your company's agent or contact the Insurance Department of PA which insurance company's rates are filed with. | 
