Each couple is different and the time element is strictly up to "when the time is right, you will know". you can plan, you can set a date to ask the question, but nature does not work that way. human emotions will set the stage and mother nature will control the situation. my wife and i dated six months. been married now 40 years. you will know and you will remember this answer, because its the truth. good luck.

it depends, how well you understand each other, how you take care of each other. the time is not defined for that certainly as some couple takes much to decide about, and always ego,fear factors come into picture, what if he/she says NO. If you people are get going well (dont count physical relationship here), the relationship of caring, how much you miss each other If u dont meet,it should get deeper day by day. And yes, more than that, you people must be understanding each other's positive and negative points. and decide, whether you will be able to stay with this person for the rest of ur life, depends on how much you love eachother and how understanding younpeople are. its not all about proposing, but its little observation of his/her positive and negative points, loving and caring, if mutual is always great, should not be one sided love. and yes, be sure that u know the difference between love and infactuation. just see urself with the person after 5 years, putting all together ur ambitions, ur career, children how well he/she will get adjusted. no need to discuss with him/her, just give it a thought with that perspective too. if you are satisfied 60-70 percent than its good, can think of propose always from ur side. but when to propose, thats again defficult to answer, buy you will feel that this is a time to say, because dont forget that what you r feeling, he/she must be feeling the same mor or less. so right time is with you after you find all above things together, just go and propose, and do not have any fear. Best of Luck.