Hello student I'm sorry to Inform you but no after one year you're not eligible you're eligible in this year itself as eligibility criteria says that Candidates must be eligible to hold an Indian passport. And candidates Date of born is must between 1 January 2005 to 31st December 2006.
For more updates refer to the link mentioned below
https://olympiads.hbcse.tifr.res.in/how-to-participate/eligibility/science-olympiad/
Feel free to comment if you have any doubt
Good luck