If you are good in research and planning then anyday planning your own is good. otherwise travel agency. Priya, also take care of basic safety rules like never reach a new place at night. Avoid secluded places if possible stick to other travellers. Be aware but also believe in basic humanity. People are good so, you are never solo as per say. Company of strangers can be really good. Still if you want to venture Himachal Pradesh as a solo Traveller, try Bir, small and peaceful Hamlet. it is really safe
See this depends on yourself completely whether the place you are travelling to is known to you aor not.
If you are well aware about the place then solo is good.
If you are unaware and new to the place better go through agency. Through agency they arrange mostly of group trip so in that case it is adventurous also to meetup with people.
Hello Priya, I would suggest travelling solo makes sense when you have time and can really plan a trip all alone as planning a trip all alone including everything i means literally everything including food, accommodation, travel, shopping, planing where to book your stays, where to eat your food, how to travel, how to explore the place, etc. So sometimes if you don't have right knowledge and research and experience you may end up spending a lot of money than the travel agency. Im not saying that solo travel is bad even you may travel at a very low cost than the travel agency but only when you know to plan everything. But yeah i suggest once in a life you should experience travelling solo to gain experience. HAPPY TRAVELLING.