Bro, its better you first learn programming instant of learing langauge, every language has common structure with additional features and different syntax. Once you will have complete understanding that what are the language ingredients e.g. variables, loops and database model etc then you only need to get familar with syntax that you even don't need to memorize. Better start from Asp.Net since it is easy to learn but also get familar with PHP once you have some grip on .Net.
I will tell feature of both of them.Your wish to select which one is best suite you select it
ASP.NET is developed by Microsoft technologies it support many scripting languages C#,visual c++,J#,F#,VB.net,etc., but php support one scripting language (java script excluded) php developed by community no standard is changeable on day to day.ASP.net is propratery software and php is free software