Hi Rabbis, what would constitute as a bar mitzvah for a Jew that didn’t have one at 13, putting on teffilin for the first time or getting called for a Aliyah for the first time? As I am writing this I figure getting an aliyah is of greater significance since you can’t do both on Shabbos or Yom Tov? Asking in the case of a grown adult way past bar mitzvah age.

Bar Mitzva is celebrating one's entering into the obligation of mitzvot. Accordingly, whether he celebrated it or not, at 13 he was already automatically Bar Mitzvah. If one feels that he missed out by not having a celebration, he can do so by having an aliya to the Torah and can decide whether he wants to tell others about this event, and if he wants to make a celebration, but there is no obligation. Any time he puts on tefilin is great (and he can call that his Bar Mitzva if that will get him to put on tefilin- even once, but how much more so, if he will begin tefilin every day, that is that much more reason to celebrate (for he is actually choosing to "enter into mitzvot")!! In short, doing the Godly mitzvah is more important than calling it a "Bar Mitzva", but if that will get him "into it", great!