My password is not working on my Mac app how can I get in to reset it

Easiest method is to restart in the Recovery Partition (hold down Command + R on startup), then open Terminal and type resetpassword and follow the on-screen prompts. 

Please follow the instructions, if you continue to have problems please be specific when you say "having a hard time getting in my computer", we have no idea what you mean. Is the room locked and you cannot get to the computer or are you saying your arms are too short or what? :-)