Although the official cut-off marks for GATE2018 will be declared by IIT in mid-March 2018, according to previous year cut-offs and toughness of paper this year following are the predictions for the cut-off of Mechanical Engineering Branch:

• General - 30 to 32
• OBC - 27 to 29
• SC/ST/PWD - 18 to 20

According to this, you will easily get qualified. Although it is tough to get admission in good IIT, I think you should explore other options and wait for the actual result.

Meanwhile, you can check Career360 website for more accurate predictions and college selection:

Https://engineering.careers360.com/gate-college-predictor?icn=gate-clgpd&ici=quick_links

https://engineering.careers360.com/articles/what-good-gate-score, open this link 

According to my research, after comparing your score with previous year record, you're qualifying Gate 2018, be it any stream

I can't make false promise, so better calculate your score in https://engineering.careers360.com/gate-college-predictor?icn=gate-clgpd&ici=quick_links

I am sure you'll get the best, All the best..!!