hello aspirant...

hope you are doing good...
yes. since 2018, UPSC allows aspirants to give papers in different languages.

These options will be available when you fill out the prelim application form. UPSC requests optional subject and medium for both GS and Essay papers, as well as Optional subject separately in the preliminary stage. So you have plenty of time to prepare and practice your chosen language.

Furthermore, if you write your GS papers in English but want to interview in Marathi, that option is available. However, if your medium for mains is Marathi/regional languages, you cannot choose English for the interview.

So, go ahead without hesitation or concern if you are more comfortable writing in English for Optional and confident writing in Hindi or any other regional language for GS and Essay papers (VIII Schedule languages).

Hope this information helps you...

all the best.