Jahiera is ballpark of about 150, which even for half-elves is past geriatric and on her way to ancient. That isn't to say she isn't deserving of love, but it is to say she might break a hip if things get too vigorous.
Honestly though, Larian made it clear that there were only 2 non-origins that were full romance partners, And we've seen both Halsin and Minthara in action.
Additionally, I doubt WoTC would freely give that level of control over two of their more beloved characters and put them in a romance situation. Hell, Minsc was never romanceable in the originals either IIRC, so no doubt he is off the table. Though, maybe you could get some alone time with Boo if it turns out he was a druid all along.
