For a business to apply for a Labour Market Impact Assessment (LMIA) in Canada, it generally needs to meet specific requirements set by Employment and Social Development Canada (ESDC). One of these requirements is that the business should be well-established and financially stable. While there isn't a strict minimum age for a business to be eligible to apply for an LMIA, there are several factors that can demonstrate the establishment and stability of the business:

1. Operational History: The business should have been operational long enough to demonstrate financial stability and the ability to pay the wages of the foreign worker. Typically, having been in operation for at least one year (especially for PR-Stream LMIA) can help to meet this criterion, but newer businesses  may also be considered (for Low-wage LMIA applications) if they can provide strong evidence of financial health and a viable business model. 

2. Financial Statements: The business must provide recent financial statements, including balance sheets, income statements, and possibly tax returns, to demonstrate financial health and the ability to pay the foreign worker's wages. OR an attestation letter by a CPA or a lawyer, confirming that the business is engaged in a legal business and provides good or a service in Canada. Read more https://www.canada.ca/en/employment-social-development/services/foreign-workers/business-legitimacy.html 

3. Business License: The business must hold a valid business license, and all required permits and licenses must be up-to-date. Few municipalities may or may not have a mandatory requirement of an operational license, therefore always read the municpality requirments where the business is located.

4. Workplace Compliance: The business must be compliant with relevant federal and provincial laws and regulations, including employment standards, occupational health and safety, and labour relations laws, depending on province. Always read the provincial requirements and guidelines.

5. Recruitment Efforts: The employer must demonstrate genuine efforts to recruit and hire Canadian citizens or permanent residents before applying for an LMIA. This includes providing evidence of advertising and recruitment efforts at Job Bank website and 2 additional methods of recruitment targeting different groups, irrespective the type of application high wage or low wage. Read more https://www.canada.ca/en/employment-social-development/services/foreign-workers/median-wage/low/requirements.html 

6. Operational Details: The employer must provide detailed information about the business operations, including the nature of the business, number of employees, and any relevant operational details that can demonstrate the business’s stability and capacity to employ a foreign worker.

7. Prevailing Wage and Offered Wage: It is important to note that the offered wage to the TFW must always be equal to or more than the median wage and can never be lower than the prevailing wage as per the job position in that province. Job Bank Canada's Wage report must always be consulted as the wages are revised at provincial level and it is important to stay updated with the right wage rate. Search wage according to occupation and location here https://www.jobbank.gc.ca/trend-analysis/search-occupations 

Simply put, for PR-stream LMIA application (also known as Dual-intent), the business must be at least 1 year old and all proofs of the business operations must be provided with the LMIA application to ESDC.

For detailed guidelines, it is advisable to consult the Government of Canada's official guidelines or seek advice from an immigration consultant or lawyer.