Well just because someone is older doesnt neccessarily mean they are mature, or honest for that matter. I dont know this lady so I cant judge her situation but I feel you are owed more of an explanation than she is giving you. I am only 25 years old, but I would be honest with a man if I was either not into him physically, or if there was some other reason I wasnt ready (like if Id been raped, or had confidence issues, or something like that). There are many reasons she might not be ready, and you deserve to know more about what is going on within your relationship. Its also entirely possible she is just using you for emotional support while she acts out her physical lust with someone else. There is a real lack of communication going on here it seems.