Well what people usually regret is what they have not done... (all within reason)
one possibility could be:
-saying you like her, and if she could imagine if something might develop, and you want to take it slow...
well she could say yes or no...
if she says no you could say ok lets stay friends... and continue the friendship...
well imo there is no need to ask her out... just hinting at that you'd like to see more... and like to take it slow...
well its up to you