With a JEE Mains rank of 18,000 in the General category, you may have a chance to get into some newer or less competitive NITs (National Institutes of Technology) and IIITs (Indian Institutes of Information Technology) for Computer Science. Colleges like NIT Mizoram, NIT Nagaland, IIIT Kota, or IIIT Allahabad (for certain categories) may have cutoffs that align with your rank. However, cutoff trends vary each year, so checking the latest information from JoSAA counseling is crucial.