Meh!
7.O-O is better than 7...exd5. After 7...O-O 8.Re1, best for both sides is 8...b5 9.e5! (NOT 9.exd5) Nd7 10.Nf1 a5 11.h4 b4 12.N1h2 Ba6 and now:
13.Ng5 Qe8! 14.Qh5 h6 with ...f5 coming where the Queen will be hanging and en passant is not possible, so Black shuts down the center completely.
13.Bf4 a4 14.a3 (Forced! - White cannot afford to allow ...a3 by Black. If then b3, there is a big hole on c3 for a Knight once the Dark Bishops are traded off) 14...bxa3 15.bxa3 with a game.
13.Ng4 Nd4 (13...a4 is also fine here) 14.Nxd4 (forced as if he does not do it, 14...Nf5 with defend everything!) 14...cxd4 and Black has play down the c-file and a target at c2 to offset his compromised pawn structure.
13.Bf4 and 13.Ng4 are considered stronger than 13.Ng5.
Do u know King's Indian attack? King's Indian attack is an opening which is highly beneficial against silican defence, French defence and caro- kan defence. If u want to know more or what it is or how to play. Check out my new blog- King's Indian Attack - Chess.com https://www.chess.com/blog/ADITHYA_SMART/kings-indian-attack
Hope u like it. Have a nice day