1. I will be 14 years old next year.

2. I shall be 14 years old next year.
3. I am going to be 14 years old next year.
4. I intend to be 14 years old next year.

(Are they the same? What is the difference between 'will' and 'be going to'?)

"Will" and "going to" are the same.

"I intend to be 14 years old next year" and "I shall be 14 years old next year" mean the same thing. It's something we'd never really say. It means you want to be 14 and will try to make it happen. It means something like, "I want to be 14 years old next year and I will work to be that old next year."
How can you do that? You either will be 14 or you won't. :-)
A 11 year old won't hope he magically turns 14 next year without needing serious medication. :-)

1. "I will be 14 years old next year." In this sentence, "will" is used to express a future event or action that is planned or expected to happen. In this case, it means that the speaker expects or plans to turn 14 years old next year.

2. "I shall be 14 years old next year." Similar to the previous sentence, "shall" is also used to express a future event or action. However, in modern English, "shall" is rarely used, and it can be considered old-fashioned or formal.

3. "I am going to be 14 years old next year." This sentence uses the phrase "going to" to indicate a future event or action. "Going to" is commonly used to express plans or intentions for the future. It implies that the action or event is already planned or decided.

4. "I intend to be 14 years old next year." This sentence uses the verb "intend," which means to have a plan or purpose in mind. "Intend to" indicates a future action that the speaker plans or aims to do.

All four sentences convey the same meaning, that the speaker expects or plans to turn 14 years old in the coming year. The difference lies in the choice of words and phrases used to express the future event.