Not disputing the itinerary is invalid, but, as others have said, you should be able to make the connection.
It's been hinted at but not said explicitly: the itinerary has given you 17 minutes to get from the main Paddington station to the Elizabeth Line. That is easily done, and I expect you'll end up on an Elizabeth Line train that departs several minutes earlier than the one in your itinerary, thus giving you more than the suggested 4 minutes to make the connection onto the Thameslink service at Farringdon.
I do a journey involving a Paddington to Farringdon connection 3 or 4 times a year, with a large suitcase, and assuming there's no disruption, I've always managed to make an "unofficial" connection from a xx:29 arrival in Paddington onto a xx:56 departure from Farringdon (2 minutes less than you've been given), with several minutes to spare. So it probably takes just over 20 minutes.
If you're at all worried it may help to know the route you need to take to minimise walking distance. This is from memory, so happy to be corrected by anyone who does the journey more often than me:
- Get off the train at Paddington, go towards the front of the train and through the barriers to the main concourse
- Turn right, heading towards to platform 1
- Leave the station at the exit near platform 1
- The escalators to the Elizabeth Line are in front of you
- Go down the first escalator, and then continue straight ahead through the ticket barriers in front of you (don't use the barriers behind you)
- Go down the second escalator, the line you want is on the right when you get to the bottom
- Keep going ahead from the bottom of the escalator towards the end of the platform, so you end up near the back of the train when it arrives
- Get off at Farringdon, and look for the lifts, which are in the exit route near the back of the train
- Use the lift to go the middle of the three floors available. The floors are bizarrely numbered, I forget exactly how, but something like 0, -2 and -7. Whatever they are, pick the middle one.
- The lift brings you out directly onto the southbound Thameslink platform for trains towards London Bridge