Project Idea Doubt

[J0SAL]

I am trying to create a new project through which a user will be able to track his/her expenses, this is the initial contract i came up with,

I wanted to know some opinions/views on this project, am I doing it the right way?

contract ExpenseTracker{
    enum TransactionType{ INCOME, EXPENSE }
    struct Transaction{
        TransactionType t_type;
        string t_disc;
        uint256 t_amount;
    }
    mapping(address => Transaction[]) private transactions;

    function addExpense(uint amount, string memory desc) public {
        transactions[msg.sender].push(Transaction(
            TransactionType.EXPENSE,
            desc,
            amount
        ));
    }
    function addIncome(uint amount, string memory desc) public {
        transactions[msg.sender].push(Transaction(
            TransactionType.INCOME,
            desc,
            amount
        ));
    }
    function getUserTransactions() public view returns (Transaction[] memory){
        return transactions[msg.sender];
    }
    function getUserTransactionsLen() public view returns (uint){
        return transactions[msg.sender].length;
    }
}

addExpense() - adds user expense
addIncome() - adds user income
getUserTransactions() - get all transactions done by the user.
getUserTransactionsLen() - get the length of all transactions done by the user.

Imp points:

1. I want to keep the contract specifically for a single user, so can I do something by using the constructor?