In one month you seem to have changed your resolve. In your last post you told us that you are a virgin and saving all your cum for your future wife. But then resolves are to be broken and when you are thinking with an erection and not with your head I do not blame you.
You have told us about your fetish for opening the legs of mature women and MILFs so getting an invitation from a 50 year old woman must be like honey to your ears.
However you may be jumping to conclusions. It is possible that she is only being friendly to a 29 year old colleague. Her inviting you when you are around could be a social gesture. No need to get an it is.erection so soon.
Why are you asking us if it is wrong? You know it is. You also think that you are God's answer to all mature women. You are a Virgin, do not have a girlfriend and have no experience of what women desire. So stop thinking that you are better than most uncles. For all you know, you may ejaculate with your first stroke.
You have still a long way to go in understanding what mature women want.
Grab the opportunity with both hands because it is rare thing men get so do not lose it thinking that whether it is immoral or not. If your guts are telling you that she wants intimate relationship with you then you should believe your guts and act on it but smartly so if your guts are on wrong side you can manage to get out of the situation so sent hints to her that you want to visit her house and see her reactions. Her reactions will make many things clear so just spark up the conversation and spend your most of time in between her legs.
You can have sex with her without condom if you are sure about her health or aware of her sexual history. It would be better to set boundaries for both of you before starting sexual relationship so no one would feel used one later on. I had sex with many women but let me tell you distinctively that mature women are much better than younger one so you have a great chance to enjoy mature body so do not lose this occasion.
The women in her 50s may think something different from you. You are a young chap and she has expertise. Social gestures cannot be taken as granted because without knowing the person you are predicting her character and mind which would be suit to you. Its biasness.
Sex without condom is always risky because women in this age maynot be pregnant but the chance of getting infected would be more.
If she is allowing her for sex then you are lucky and don’t miss the chance. She would be your sex teacher and can able to teach you better. If you are thinking about moral values then return back.