Error

Hola , buenas noches tengo este error y no se como solucionarlo TypeError: Cannot read properties of null (reading 'querySelector')

código java var paciente = document.querySelector("#primer-paciente"); var w = paciente.querySelector(".info-peso"); var weight = w.textContent; var h = paciente.querySelector(".info-altura"); var height = h.textContent; var tdIMD = paciente.querySelector(".info-imc") const Imc = weight/(height*height); tdIMD.textContent = Imc; console.log(Imc);

codigo html

    <header>
        <div class="container">
            <h1>Buona Vita Nutrición</h1>
        </div>
    </header>
    <main>
        <section class="container">
            <h2>Mis pacientes</h2>
            <table>
                <thead>
                    <tr>
                        <th>Nombre</th>
                        <th>Peso(kg)</th>
                        <th>Altura(m)</th>
                        <th>Gordura Corporal(%)</th>
                        <th>IMC</th>
                    </tr>
                </thead>
                <tbody id="tabla-pacientes">
                    <tr class="primer-paciente">
                        <td class="info-nombre">Pablo</td>
                        <td class="info-peso">100</td>
                        <td class="info-altura">2.00</td>
                        <td class="info-gordura">10</td>
                        <td class="info-imc">0</td>
                    </tr>

                    <tr class="paciente" >
                        <td class="info-nombre">Juan</td>
                        <td class="info-peso">80</td>
                        <td class="info-altura">1.72</td>
                        <td class="info-gordura">40</td>
                        <td class="info-imc">0</td>
                    </tr>

                    <tr class="paciente" >
                        <td class="info-nombre">Erica</td>
                        <td class="info-peso">54</td>
                        <td class="info-altura">1.64</td>
                        <td class="info-gordura">14</td>
                        <td class="info-imc">0</td>
                    </tr>

                    <tr class="paciente">
                        <td class="info-nombre">Diego</td>
                        <td class="info-peso">85</td>
                        <td class="info-altura">1.73</td>
                        <td class="info-gordura">24</td>
                        <td class="info-imc">0</td>
                    </tr>
                    <tr class="paciente" >
                        <td class="info-nombre">Tatiana</td>
                        <td class="info-peso">46</td>
                        <td class="info-altura">1.55</td>
                        <td class="info-gordura">19</td>
                        <td class="info-imc">0</td>
                    </tr>
                </tbody>
            </table>

        </section>
    </main>

</body>