No, the choice is yours.
The social Internet offer means you get fixed Internet access for the price of 19 euro per month (or 40 euro for a bundle). The social Internet offer includes 150 GB of data and a minimum speed of 30 Mbps. If that does not meet your requirements you cankeep your old social tariff, which consists of a maximum discount of 11.5 euro on your telecom bill.
However, by accepting the social Internet offer you can no longer apply again for a social discount on a normal telecom subscription (“old” social tariff) later on. So check, before changing, if the social internet offer corresponds to the needs of your household.