Yes, you can start a sentence with the word ‘so.’ In fact, it’s a common practice in conversational English. ‘So’ can be used to indicate a conclusion or a result of something previously mentioned. For example, if someone says, ‘I forgot my umbrella,’ you might respond, ‘So, you got wet in the rain.’
Using ‘so’ at the beginning of a sentence can also serve as a way to transition between thoughts or to indicate a change in topic. However, in formal writing, some might advise against starting with ‘so’ to maintain a more traditional and structured style. Ultimately, whether to use ‘so’ at the beginning of a sentence depends on the context and the tone you wish to convey.