Why do you want to take everyone's guns away? Don't you think we can find solutions that do not take guns from law abiding citizens? 
Do you have any evidence that a 90 day waiting period would not reduce gun violence? It might have made a difference in Orlando.  Wouldn't it be worth it to try something and then try something else and then try something else until we can find what works in reducing gun violence? Taking all guns away is not the solution and would be one that I would strongly oppose. I'm sorry you think this is the only solution.