Loneliness, and satisfaction in it is quite different from forced loneliness and not satisfied with it and is quite different from self-imposed isolation because of apprehensions.
In this age of jet setting world, there are very many dynamic youth who do not see the need of marriage till a certain age. And in fact, statistics attest to this; the age of marriage for both the genders has gone up, over the period of last few decades.
In the western world, there are more individuals living alone because of varied many reasons, and the trend is catching up in India too.
The issue is not about marriage but about relationships and friendships.
If you are comfortable with your friends as both acquaintances and friends there is no reason to worry.
If you are comfortable alone and prefer lonely pursuits although there is no dearth of friends then it might be what you are meant to be that is it might be your personality style.
If you are not comfortable alone, but are not able to relate to others because of either your apprehensions / anxieties, this might be controllable with specific management.
Apprehensions can be because of anxieties of how to interact with a person of the opposite gender, of how to maintain friends, how to speak and interact amongst others, of being in a new place/environment, of being in a new group of people, of being in a different culture etc.
It seems by the very fact of you asking a question that you are seemingly not comfortable with the isolation. You need to self evaluate according to the above presented scenarios and take a step.